2 <!DOCTYPE modulesynopsis SYSTEM "../style/modulesynopsis.dtd">
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7 Copyright 2002-2006 The Apache Software Foundation or its licensors, as
10 Licensed under the Apache License, Version 2.0 (the "License");
11 you may not use this file except in compliance with the License.
12 You may obtain a copy of the License at
14 http://www.apache.org/licenses/LICENSE-2.0
16 Unless required by applicable law or agreed to in writing, software
17 distributed under the License is distributed on an "AS IS" BASIS,
18 WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
19 See the License for the specific language governing permissions and
20 limitations under the License.
23 <modulesynopsis metafile="core.xml.meta">
26 <description>Core Apache HTTP Server features that are always
27 available</description>
31 <name>AcceptFilter</name>
32 <description>Configures optimizations for a Protocol's Listener Sockets</description>
33 <syntax>AcceptFilter <var>protocol</var> <var>accept_filter</var></syntax>
34 <contextlist><context>server config</context></contextlist>
35 <compatibility>Available in Apache 2.1.5 and later</compatibility>
38 <p>This directive enables operating system specific optimizations for a
39 listening socket by the Protocol type. The basic premise is for the
40 kernel to not send a socket to the server process until either data
41 is received or an entire HTTP Request is buffered. Only
42 <a href="http://www.freebsd.org/cgi/man.cgi?query=accept_filter&sektion=9">
43 FreeBSD's Accept Filters</a> and Linux's more primitive
44 <code>TCP_DEFER_ACCEPT</code> are currently supported.</p>
46 <p>The default values on FreeBSD are:</p>
48 AcceptFilter http httpready <br/>
49 AcceptFilter https dataready
52 <p>The <code>httpready</code> accept filter buffers entire HTTP requests at
53 the kernel level. Once an entire request is recieved, the kernel then
54 sends it to the server. See the
55 <a href="http://www.freebsd.org/cgi/man.cgi?query=accf_http&sektion=9">
56 accf_http(9)</a> man page for more details. Since HTTPS requests are
57 encrypted only the <a href="http://www.freebsd.org/cgi/man.cgi?query=accf_data&sektion=9">
58 accf_data(9)</a> filter is used.</p>
60 <p>The default values on Linux are:</p>
62 AcceptFilter http data <br/>
63 AcceptFilter https data
66 <p>Linux's <code>TCP_DEFER_ACCEPT</code> does not support buffering http
67 requests. Any value besides <code>none</code> will enable
68 <code>TCP_DEFER_ACCEPT</code> on that listener. For more details
70 <a href="http://homepages.cwi.nl/~aeb/linux/man2html/man7/tcp.7.html">
71 tcp(7)</a> man page.</p>
73 <p>Using <code>none</code> for an argument will disable any accept filters
74 for that protocol. This is useful for protocols that require a server
75 send data first, such as <code>nntp</code>:</p>
76 <example>AcceptFilter nttp none</example>
82 <name>AcceptPathInfo</name>
83 <description>Resources accept trailing pathname information</description>
84 <syntax>AcceptPathInfo On|Off|Default</syntax>
85 <default>AcceptPathInfo Default</default>
86 <contextlist><context>server config</context>
87 <context>virtual host</context><context>directory</context>
88 <context>.htaccess</context></contextlist>
89 <override>FileInfo</override>
90 <compatibility>Available in Apache 2.0.30 and later</compatibility>
94 <p>This directive controls whether requests that contain trailing
95 pathname information that follows an actual filename (or
96 non-existent file in an existing directory) will be accepted or
97 rejected. The trailing pathname information can be made
98 available to scripts in the <code>PATH_INFO</code> environment
101 <p>For example, assume the location <code>/test/</code> points to
102 a directory that contains only the single file
103 <code>here.html</code>. Then requests for
104 <code>/test/here.html/more</code> and
105 <code>/test/nothere.html/more</code> both collect
106 <code>/more</code> as <code>PATH_INFO</code>.</p>
108 <p>The three possible arguments for the
109 <directive>AcceptPathInfo</directive> directive are:</p>
111 <dt><code>Off</code></dt><dd>A request will only be accepted if it
112 maps to a literal path that exists. Therefore a request with
113 trailing pathname information after the true filename such as
114 <code>/test/here.html/more</code> in the above example will return
115 a 404 NOT FOUND error.</dd>
117 <dt><code>On</code></dt><dd>A request will be accepted if a
118 leading path component maps to a file that exists. The above
119 example <code>/test/here.html/more</code> will be accepted if
120 <code>/test/here.html</code> maps to a valid file.</dd>
122 <dt><code>Default</code></dt><dd>The treatment of requests with
123 trailing pathname information is determined by the <a
124 href="../handler.html">handler</a> responsible for the request.
125 The core handler for normal files defaults to rejecting
126 <code>PATH_INFO</code> requests. Handlers that serve scripts, such as <a
127 href="mod_cgi.html">cgi-script</a> and <a
128 href="mod_isapi.html">isapi-isa</a>, generally accept
129 <code>PATH_INFO</code> by default.</dd>
132 <p>The primary purpose of the <code>AcceptPathInfo</code>
133 directive is to allow you to override the handler's choice of
134 accepting or rejecting <code>PATH_INFO</code>. This override is required,
135 for example, when you use a <a href="../filter.html">filter</a>, such
136 as <a href="mod_include.html">INCLUDES</a>, to generate content
137 based on <code>PATH_INFO</code>. The core handler would usually reject
138 the request, so you can use the following configuration to enable
142 <Files "mypaths.shtml"><br />
144 Options +Includes<br />
145 SetOutputFilter INCLUDES<br />
146 AcceptPathInfo On<br />
155 <name>AccessFileName</name>
156 <description>Name of the distributed configuration file</description>
157 <syntax>AccessFileName <var>filename</var> [<var>filename</var>] ...</syntax>
158 <default>AccessFileName .htaccess</default>
159 <contextlist><context>server config</context><context>virtual host</context>
163 <p>While processing a request the server looks for
164 the first existing configuration file from this list of names in
165 every directory of the path to the document, if distributed
166 configuration files are <a href="#allowoverride">enabled for that
167 directory</a>. For example:</p>
173 <p>before returning the document
174 <code>/usr/local/web/index.html</code>, the server will read
175 <code>/.acl</code>, <code>/usr/.acl</code>,
176 <code>/usr/local/.acl</code> and <code>/usr/local/web/.acl</code>
177 for directives, unless they have been disabled with</p>
180 <Directory /><br />
182 AllowOverride None<br />
187 <seealso><directive module="core">AllowOverride</directive></seealso>
188 <seealso><a href="../configuring.html">Configuration Files</a></seealso>
189 <seealso><a href="../howto/htaccess.html">.htaccess Files</a></seealso>
193 <name>AddDefaultCharset</name>
194 <description>Default charset parameter to be added when a response
195 content-type is <code>text/plain</code> or <code>text/html</code></description>
196 <syntax>AddDefaultCharset On|Off|<var>charset</var></syntax>
197 <default>AddDefaultCharset Off</default>
198 <contextlist><context>server config</context>
199 <context>virtual host</context><context>directory</context>
200 <context>.htaccess</context></contextlist>
201 <override>FileInfo</override>
204 <p>This directive specifies a default value for the media type
205 charset parameter (the name of a character encoding) to be added
206 to a response if and only if the response's content-type is either
207 <code>text/plain</code> or <code>text/html</code>. This should override
208 any charset specified in the body of the response via a <code>META</code>
209 element, though the exact behavior is often dependent on the user's client
210 configuration. A setting of <code>AddDefaultCharset Off</code>
211 disables this functionality. <code>AddDefaultCharset On</code> enables
212 a default charset of <code>iso-8859-1</code>. Any other value is assumed
213 to be the <var>charset</var> to be used, which should be one of the
214 <a href="http://www.iana.org/assignments/character-sets">IANA registered
215 charset values</a> for use in MIME media types.
219 AddDefaultCharset utf-8
222 <p><directive>AddDefaultCharset</directive> should only be used when all
223 of the text resources to which it applies are known to be in that
224 character encoding and it is too inconvenient to label their charset
225 individually. One such example is to add the charset parameter
226 to resources containing generated content, such as legacy CGI
227 scripts, that might be vulnerable to cross-site scripting attacks
228 due to user-provided data being included in the output. Note, however,
229 that a better solution is to just fix (or delete) those scripts, since
230 setting a default charset does not protect users that have enabled
231 the "auto-detect character encoding" feature on their browser.</p>
233 <seealso><directive module="mod_mime">AddCharset</directive></seealso>
237 <name>AddOutputFilterByType</name>
238 <description>assigns an output filter to a particular MIME-type</description>
239 <syntax>AddOutputFilterByType <var>filter</var>[;<var>filter</var>...]
240 <var>MIME-type</var> [<var>MIME-type</var>] ...</syntax>
241 <contextlist><context>server config</context>
242 <context>virtual host</context><context>directory</context>
243 <context>.htaccess</context></contextlist>
244 <override>FileInfo</override>
245 <compatibility>Available in Apache 2.0.33 and later; deprecated in Apache 2.1 and later</compatibility>
248 <p>This directive activates a particular output <a
249 href="../filter.html">filter</a> for a request depending on the
250 response <glossary>MIME-type</glossary>. Because of certain
251 problems discussed below, this directive is deprecated. The same
252 functionality is available using <module>mod_filter</module>.</p>
254 <p>The following example uses the <code>DEFLATE</code> filter, which
255 is provided by <module>mod_deflate</module>. It will compress all
256 output (either static or dynamic) which is labeled as
257 <code>text/html</code> or <code>text/plain</code> before it is sent
261 AddOutputFilterByType DEFLATE text/html text/plain
264 <p>If you want the content to be processed by more than one filter, their
265 names have to be separated by semicolons. It's also possible to use one
266 <directive>AddOutputFilterByType</directive> directive for each of
269 <p>The configuration below causes all script output labeled as
270 <code>text/html</code> to be processed at first by the
271 <code>INCLUDES</code> filter and then by the <code>DEFLATE</code>
275 <Location /cgi-bin/><br />
277 Options Includes<br />
278 AddOutputFilterByType INCLUDES;DEFLATE text/html<br />
283 <note type="warning"><title>Note</title>
284 <p>Enabling filters with <directive>AddOutputFilterByType</directive>
285 may fail partially or completely in some cases. For example, no
286 filters are applied if the <glossary>MIME-type</glossary> could not be determined and falls
287 back to the <directive module="core">DefaultType</directive> setting,
288 even if the <directive module="core">DefaultType</directive> is the
291 <p>However, if you want to make sure, that the filters will be
292 applied, assign the content type to a resource explicitly, for
293 example with <directive module="mod_mime">AddType</directive> or
294 <directive module="core">ForceType</directive>. Setting the
295 content type within a (non-nph) CGI script is also safe.</p>
297 <p>The by-type output filters are never applied on proxy requests.</p>
301 <seealso><directive module="mod_mime">AddOutputFilter</directive></seealso>
302 <seealso><directive module="core">SetOutputFilter</directive></seealso>
303 <seealso><a href="../filter.html">filters</a></seealso>
307 <name>AllowEncodedSlashes</name>
308 <description>Determines whether encoded path separators in URLs are allowed to
309 be passed through</description>
310 <syntax>AllowEncodedSlashes On|Off</syntax>
311 <default>AllowEncodedSlashes Off</default>
312 <contextlist><context>server config</context><context>virtual host</context>
314 <compatibility>Available in Apache 2.0.46 and later</compatibility>
317 <p>The <directive>AllowEncodedSlashes</directive> directive allows URLs
318 which contain encoded path separators (<code>%2F</code> for <code>/</code>
319 and additionally <code>%5C</code> for <code>\</code> on according systems)
320 to be used. Normally such URLs are refused with a 404 (Not found) error.</p>
322 <p>Turning <directive>AllowEncodedSlashes</directive> <code>On</code> is
323 mostly useful when used in conjunction with <code>PATH_INFO</code>.</p>
325 <note><title>Note</title>
326 <p>Allowing encoded slashes does <em>not</em> imply <em>decoding</em>.
327 Occurrences of <code>%2F</code> or <code>%5C</code> (<em>only</em> on
328 according systems) will be left as such in the otherwise decoded URL
332 <seealso><directive module="core">AcceptPathInfo</directive></seealso>
336 <name>AllowOverride</name>
337 <description>Types of directives that are allowed in
338 <code>.htaccess</code> files</description>
339 <syntax>AllowOverride All|None|<var>directive-type</var>
340 [<var>directive-type</var>] ...</syntax>
341 <default>AllowOverride All</default>
342 <contextlist><context>directory</context></contextlist>
345 <p>When the server finds an <code>.htaccess</code> file (as
346 specified by <directive module="core">AccessFileName</directive>)
347 it needs to know which directives declared in that file can override
348 earlier configuration directives.</p>
350 <note><title>Only available in <Directory> sections</title>
351 <directive>AllowOverride</directive> is valid only in
352 <directive type="section" module="core">Directory</directive>
353 sections specified without regular expressions, not in <directive
354 type="section" module="core">Location</directive>, <directive
355 module="core" type="section">DirectoryMatch</directive> or
356 <directive type="section" module="core">Files</directive> sections.
359 <p>When this directive is set to <code>None</code>, then
360 <a href="#accessfilename">.htaccess</a> files are completely ignored.
361 In this case, the server will not even attempt to read
362 <code>.htaccess</code> files in the filesystem.</p>
364 <p>When this directive is set to <code>All</code>, then any
365 directive which has the .htaccess <a
366 href="directive-dict.html#Context">Context</a> is allowed in
367 <code>.htaccess</code> files.</p>
369 <p>The <var>directive-type</var> can be one of the following
370 groupings of directives.</p>
377 Allow use of the authorization directives (<directive
378 module="mod_authn_dbm">AuthDBMGroupFile</directive>,
379 <directive module="mod_authn_dbm">AuthDBMUserFile</directive>,
380 <directive module="mod_authz_groupfile">AuthGroupFile</directive>,
381 <directive module="core">AuthName</directive>,
382 <directive module="core">AuthType</directive>, <directive
383 module="mod_authn_file">AuthUserFile</directive>, <directive
384 module="core">Require</directive>, <em>etc.</em>).</dd>
389 Allow use of the directives controlling document types (<directive
390 module="core">DefaultType</directive>, <directive
391 module="core">ErrorDocument</directive>, <directive
392 module="core">ForceType</directive>, <directive
393 module="mod_negotiation">LanguagePriority</directive>,
394 <directive module="core">SetHandler</directive>, <directive
395 module="core">SetInputFilter</directive>, <directive
396 module="core">SetOutputFilter</directive>, and
397 <module>mod_mime</module> Add* and Remove*
398 directives, <em>etc.</em>), document meta data (<directive
399 module="mod_headers">Header</directive>, <directive
400 module="mod_headers">RequestHeader</directive>, <directive
401 module="mod_setenvif">SetEnvIf</directive>, <directive
402 module="mod_setenvif">SetEnvIfNoCase</directive>, <directive
403 module="mod_setenvif">BrowserMatch</directive>, <directive
404 module="mod_usertrack">CookieExpires</directive>, <directive
405 module="mod_usertrack">CookieDomain</directive>, <directive
406 module="mod_usertrack">CookieStyle</directive>, <directive
407 module="mod_usertrack">CookieTracking</directive>, <directive
408 module="mod_usertrack">CookieName</directive>),
409 <module>mod_rewrite</module> directives <directive
410 module="mod_rewrite">RewriteEngine</directive>, <directive
411 module="mod_rewrite">RewriteOptions</directive>, <directive
412 module="mod_rewrite">RewriteBase</directive>, <directive
413 module="mod_rewrite">RewriteCond</directive>, <directive
414 module="mod_rewrite">RewriteRule</directive>) and
415 <directive module="mod_actions">Action</directive> from
416 <module>mod_actions</module>.
422 Allow use of the directives controlling directory indexing
424 module="mod_autoindex">AddDescription</directive>,
425 <directive module="mod_autoindex">AddIcon</directive>, <directive
426 module="mod_autoindex">AddIconByEncoding</directive>,
427 <directive module="mod_autoindex">AddIconByType</directive>,
428 <directive module="mod_autoindex">DefaultIcon</directive>, <directive
429 module="mod_dir">DirectoryIndex</directive>, <directive
430 module="mod_autoindex">FancyIndexing</directive>, <directive
431 module="mod_autoindex">HeaderName</directive>, <directive
432 module="mod_autoindex">IndexIgnore</directive>, <directive
433 module="mod_autoindex">IndexOptions</directive>, <directive
434 module="mod_autoindex">ReadmeName</directive>,
440 Allow use of the directives controlling host access (<directive
441 module="mod_authz_host">Allow</directive>, <directive
442 module="mod_authz_host">Deny</directive> and <directive
443 module="mod_authz_host">Order</directive>).</dd>
445 <dt>Options[=<var>Option</var>,...]</dt>
448 Allow use of the directives controlling specific directory
449 features (<directive module="core">Options</directive> and
450 <directive module="mod_include">XBitHack</directive>).
451 An equal sign may be given followed by a comma (but no spaces)
452 separated lists of options that may be set using the <directive
453 module="core">Options</directive> command.</dd>
459 AllowOverride AuthConfig Indexes
462 <p>In the example above all directives that are neither in the group
463 <code>AuthConfig</code> nor <code>Indexes</code> cause an internal
467 <seealso><directive module="core">AccessFileName</directive></seealso>
468 <seealso><a href="../configuring.html">Configuration Files</a></seealso>
469 <seealso><a href="../howto/htaccess.html">.htaccess Files</a></seealso>
473 <name>CGIMapExtension</name>
474 <description>Technique for locating the interpreter for CGI
475 scripts</description>
476 <syntax>CGIMapExtension <var>cgi-path</var> <var>.extension</var></syntax>
477 <contextlist><context>directory</context><context>.htaccess</context>
479 <override>FileInfo</override>
480 <compatibility>NetWare only</compatibility>
483 <p>This directive is used to control how Apache finds the
484 interpreter used to run CGI scripts. For example, setting
485 <code>CGIMapExtension sys:\foo.nlm .foo</code> will
486 cause all CGI script files with a <code>.foo</code> extension to
487 be passed to the FOO interpreter.</p>
492 <name>ContentDigest</name>
493 <description>Enables the generation of <code>Content-MD5</code> HTTP Response
494 headers</description>
495 <syntax>ContentDigest On|Off</syntax>
496 <default>ContentDigest Off</default>
497 <contextlist><context>server config</context><context>virtual host</context>
498 <context>directory</context><context>.htaccess</context>
500 <override>Options</override>
501 <status>Experimental</status>
504 <p>This directive enables the generation of
505 <code>Content-MD5</code> headers as defined in RFC1864
506 respectively RFC2068.</p>
508 <p>MD5 is an algorithm for computing a "message digest"
509 (sometimes called "fingerprint") of arbitrary-length data, with
510 a high degree of confidence that any alterations in the data
511 will be reflected in alterations in the message digest.</p>
513 <p>The <code>Content-MD5</code> header provides an end-to-end
514 message integrity check (MIC) of the entity-body. A proxy or
515 client may check this header for detecting accidental
516 modification of the entity-body in transit. Example header:</p>
519 Content-MD5: AuLb7Dp1rqtRtxz2m9kRpA==
522 <p>Note that this can cause performance problems on your server
523 since the message digest is computed on every request (the
524 values are not cached).</p>
526 <p><code>Content-MD5</code> is only sent for documents served
527 by the <module>core</module>, and not by any module. For example,
528 SSI documents, output from CGI scripts, and byte range responses
529 do not have this header.</p>
534 <name>DefaultType</name>
535 <description>MIME content-type that will be sent if the
536 server cannot determine a type in any other way</description>
537 <syntax>DefaultType <var>MIME-type</var></syntax>
538 <default>DefaultType text/plain</default>
539 <contextlist><context>server config</context><context>virtual host</context>
540 <context>directory</context><context>.htaccess</context>
542 <override>FileInfo</override>
545 <p>There will be times when the server is asked to provide a
546 document whose type cannot be determined by its <glossary
547 ref="mime-type">MIME types</glossary> mappings.</p>
549 <p>The server must inform the client of the content-type of the
550 document, so in the event of an unknown type it uses the
551 <code>DefaultType</code>. For example:</p>
554 DefaultType image/gif
557 <p>would be appropriate for a directory which contained many GIF
558 images with filenames missing the <code>.gif</code> extension.</p>
560 <p>Note that unlike <directive
561 module="core">ForceType</directive>, this directive only
562 provides the default mime-type. All other mime-type definitions,
563 including filename extensions, that might identify the media type
564 will override this default.</p>
568 <directivesynopsis type="section">
569 <name>Directory</name>
570 <description>Enclose a group of directives that apply only to the
571 named file-system directory and sub-directories</description>
572 <syntax><Directory <var>directory-path</var>>
573 ... </Directory></syntax>
574 <contextlist><context>server config</context><context>virtual host</context>
578 <p><directive type="section">Directory</directive> and
579 <code></Directory></code> are used to enclose a group of
580 directives that will apply only to the named directory and
581 sub-directories of that directory. Any directive that is allowed
582 in a directory context may be used. <var>Directory-path</var> is
583 either the full path to a directory, or a wild-card string using
584 Unix shell-style matching. In a wild-card string, <code>?</code> matches
585 any single character, and <code>*</code> matches any sequences of
586 characters. You may also use <code>[]</code> character ranges. None
587 of the wildcards match a `/' character, so <code><Directory
588 /*/public_html></code> will not match
589 <code>/home/user/public_html</code>, but <code><Directory
590 /home/*/public_html></code> will match. Example:</p>
593 <Directory /usr/local/httpd/htdocs><br />
595 Options Indexes FollowSymLinks<br />
601 <p>Be careful with the <var>directory-path</var> arguments:
602 They have to literally match the filesystem path which Apache uses
603 to access the files. Directives applied to a particular
604 <code><Directory></code> will not apply to files accessed from
605 that same directory via a different path, such as via different symbolic
609 <p><glossary ref="regex">Regular
610 expressions</glossary> can also be used, with the addition of the
611 <code>~</code> character. For example:</p>
614 <Directory ~ "^/www/.*/[0-9]{3}">
617 <p>would match directories in <code>/www/</code> that consisted of
620 <p>If multiple (non-regular expression) <directive
621 type="section">Directory</directive> sections
622 match the directory (or one of its parents) containing a document,
623 then the directives are applied in the order of shortest match
624 first, interspersed with the directives from the <a
625 href="#accessfilename">.htaccess</a> files. For example,
629 <Directory /><br />
631 AllowOverride None<br />
633 </Directory><br />
635 <Directory /home/><br />
637 AllowOverride FileInfo<br />
642 <p>for access to the document <code>/home/web/dir/doc.html</code>
646 <li>Apply directive <code>AllowOverride None</code>
647 (disabling <code>.htaccess</code> files).</li>
649 <li>Apply directive <code>AllowOverride FileInfo</code> (for
650 directory <code>/home</code>).</li>
652 <li>Apply any <code>FileInfo</code> directives in
653 <code>/home/.htaccess</code>, <code>/home/web/.htaccess</code> and
654 <code>/home/web/dir/.htaccess</code> in that order.</li>
657 <p>Regular expressions are not considered until after all of the
658 normal sections have been applied. Then all of the regular
659 expressions are tested in the order they appeared in the
660 configuration file. For example, with</p>
663 <Directory ~ abc$><br />
665 # ... directives here ...<br />
670 <p>the regular expression section won't be considered until after
671 all normal <directive type="section">Directory</directive>s and
672 <code>.htaccess</code> files have been applied. Then the regular
673 expression will match on <code>/home/abc/public_html/abc</code> and
674 the corresponding <directive type="section">Directory</directive> will
677 <p><strong>Note that the default Apache access for
678 <code><Directory /></code> is <code>Allow from All</code>.
679 This means that Apache will serve any file mapped from an URL. It is
680 recommended that you change this with a block such
684 <Directory /><br />
686 Order Deny,Allow<br />
692 <p><strong>and then override this for directories you
693 <em>want</em> accessible. See the <a
694 href="../misc/security_tips.html">Security Tips</a> page for more
695 details.</strong></p>
697 <p>The directory sections occur in the <code>httpd.conf</code> file.
698 <directive type="section">Directory</directive> directives
699 cannot nest, and cannot appear in a <directive module="core"
700 type="section">Limit</directive> or <directive module="core"
701 type="section">LimitExcept</directive> section.</p>
703 <seealso><a href="../sections.html">How <Directory>,
704 <Location> and <Files> sections work</a> for an
705 explanation of how these different sections are combined when a
706 request is received</seealso>
709 <directivesynopsis type="section">
710 <name>DirectoryMatch</name>
711 <description>Enclose directives that apply to
712 file-system directories matching a regular expression and their
713 subdirectories</description>
714 <syntax><DirectoryMatch <var>regex</var>>
715 ... </DirectoryMatch></syntax>
716 <contextlist><context>server config</context><context>virtual host</context>
720 <p><directive type="section">DirectoryMatch</directive> and
721 <code></DirectoryMatch></code> are used to enclose a group
722 of directives which will apply only to the named directory and
723 sub-directories of that directory, the same as <directive
724 module="core" type="section">Directory</directive>. However, it
725 takes as an argument a <glossary ref="regex">regular
726 expression</glossary>. For example:</p>
729 <DirectoryMatch "^/www/(.+/)?[0-9]{3}">
732 <p>would match directories in <code>/www/</code> that consisted of three
735 <seealso><directive type="section" module="core">Directory</directive> for
736 a description of how regular expressions are mixed in with normal
737 <directive type="section">Directory</directive>s</seealso>
739 href="../sections.html">How <Directory>, <Location> and
740 <Files> sections work</a> for an explanation of how these different
741 sections are combined when a request is received</seealso>
745 <name>DocumentRoot</name>
746 <description>Directory that forms the main document tree visible
747 from the web</description>
748 <syntax>DocumentRoot <var>directory-path</var></syntax>
749 <default>DocumentRoot /usr/local/apache/htdocs</default>
750 <contextlist><context>server config</context><context>virtual host</context>
754 <p>This directive sets the directory from which <program>httpd</program>
755 will serve files. Unless matched by a directive like <directive
756 module="mod_alias">Alias</directive>, the server appends the
757 path from the requested URL to the document root to make the
758 path to the document. Example:</p>
761 DocumentRoot /usr/web
765 <code>http://www.my.host.com/index.html</code> refers to
766 <code>/usr/web/index.html</code>. If the <var>directory-path</var> is
767 not absolute then it is assumed to be relative to the <directive
768 module="core">ServerRoot</directive>.</p>
770 <p>The <directive>DocumentRoot</directive> should be specified without
771 a trailing slash.</p>
773 <seealso><a href="../urlmapping.html">Mapping URLs to Filesystem
774 Location</a></seealso>
778 <name>EnableMMAP</name>
779 <description>Use memory-mapping to read files during delivery</description>
780 <syntax>EnableMMAP On|Off</syntax>
781 <default>EnableMMAP On</default>
782 <contextlist><context>server config</context><context>virtual host</context>
783 <context>directory</context><context>.htaccess</context>
785 <override>FileInfo</override>
788 <p>This directive controls whether the <program>httpd</program> may use
789 memory-mapping if it needs to read the contents of a file during
790 delivery. By default, when the handling of a request requires
791 access to the data within a file -- for example, when delivering a
792 server-parsed file using <module>mod_include</module> -- Apache
793 memory-maps the file if the OS supports it.</p>
795 <p>This memory-mapping sometimes yields a performance improvement.
796 But in some environments, it is better to disable the memory-mapping
797 to prevent operational problems:</p>
800 <li>On some multiprocessor systems, memory-mapping can reduce the
801 performance of the <program>httpd</program>.</li>
802 <li>With an NFS-mounted <directive module="core">DocumentRoot</directive>,
803 the <program>httpd</program> may crash due to a segmentation fault if a file
804 is deleted or truncated while the <program>httpd</program> has it
808 <p>For server configurations that are vulnerable to these problems,
809 you should disable memory-mapping of delivered files by specifying:</p>
815 <p>For NFS mounted files, this feature may be disabled explicitly for
816 the offending files by specifying:</p>
819 <Directory "/path-to-nfs-files">
829 <name>EnableSendfile</name>
830 <description>Use the kernel sendfile support to deliver files to the client</description>
831 <syntax>EnableSendfile On|Off</syntax>
832 <default>EnableSendfile On</default>
833 <contextlist><context>server config</context><context>virtual host</context>
834 <context>directory</context><context>.htaccess</context>
836 <override>FileInfo</override>
837 <compatibility>Available in version 2.0.44 and later</compatibility>
840 <p>This directive controls whether <program>httpd</program> may use the
841 sendfile support from the kernel to transmit file contents to the client.
842 By default, when the handling of a request requires no access
843 to the data within a file -- for example, when delivering a
844 static file -- Apache uses sendfile to deliver the file contents
845 without ever reading the file if the OS supports it.</p>
847 <p>This sendfile mechanism avoids separate read and send operations,
848 and buffer allocations. But on some platforms or within some
849 filesystems, it is better to disable this feature to avoid
850 operational problems:</p>
853 <li>Some platforms may have broken sendfile support that the build
854 system did not detect, especially if the binaries were built on
855 another box and moved to such a machine with broken sendfile
857 <li>On Linux the use of sendfile triggers TCP-checksum
858 offloading bugs on certain networking cards when using IPv6.</li>
859 <li>On Linux on Itanium, sendfile may be unable to handle files
860 over 2GB in size.</li>
861 <li>With a network-mounted <directive
862 module="core">DocumentRoot</directive> (e.g., NFS or SMB),
863 the kernel may be unable to serve the network file through
867 <p>For server configurations that are vulnerable to these problems,
868 you should disable this feature by specifying:</p>
874 <p>For NFS or SMB mounted files, this feature may be disabled explicitly
875 for the offending files by specifying:</p>
878 <Directory "/path-to-nfs-files">
888 <name>ErrorDocument</name>
889 <description>What the server will return to the client
890 in case of an error</description>
891 <syntax>ErrorDocument <var>error-code</var> <var>document</var></syntax>
892 <contextlist><context>server config</context><context>virtual host</context>
893 <context>directory</context><context>.htaccess</context>
895 <override>FileInfo</override>
896 <compatibility>Quoting syntax for text messages is different in Apache
900 <p>In the event of a problem or error, Apache can be configured
901 to do one of four things,</p>
904 <li>output a simple hardcoded error message</li>
906 <li>output a customized message</li>
908 <li>redirect to a local <var>URL-path</var> to handle the
911 <li>redirect to an external <var>URL</var> to handle the
915 <p>The first option is the default, while options 2-4 are
916 configured using the <directive>ErrorDocument</directive>
917 directive, which is followed by the HTTP response code and a URL
918 or a message. Apache will sometimes offer additional information
919 regarding the problem/error.</p>
921 <p>URLs can begin with a slash (/) for local web-paths (relative
922 to the <directive module="core">DocumentRoot</directive>), or be a
923 full URL which the client can resolve. Alternatively, a message
924 can be provided to be displayed by the browser. Examples:</p>
927 ErrorDocument 500 http://foo.example.com/cgi-bin/tester<br />
928 ErrorDocument 404 /cgi-bin/bad_urls.pl<br />
929 ErrorDocument 401 /subscription_info.html<br />
930 ErrorDocument 403 "Sorry can't allow you access today"
933 <p>Additionally, the special value <code>default</code> can be used
934 to specify Apache's simple hardcoded message. While not required
935 under normal circumstances, <code>default</code> will restore
936 Apache's simple hardcoded message for configurations that would
937 otherwise inherit an existing <directive>ErrorDocument</directive>.</p>
940 ErrorDocument 404 /cgi-bin/bad_urls.pl<br /><br />
941 <Directory /web/docs><br />
943 ErrorDocument 404 default<br />
948 <p>Note that when you specify an <directive>ErrorDocument</directive>
949 that points to a remote URL (ie. anything with a method such as
950 <code>http</code> in front of it), Apache will send a redirect to the
951 client to tell it where to find the document, even if the
952 document ends up being on the same server. This has several
953 implications, the most important being that the client will not
954 receive the original error status code, but instead will
955 receive a redirect status code. This in turn can confuse web
956 robots and other clients which try to determine if a URL is
957 valid using the status code. In addition, if you use a remote
958 URL in an <code>ErrorDocument 401</code>, the client will not
959 know to prompt the user for a password since it will not
960 receive the 401 status code. Therefore, <strong>if you use an
961 <code>ErrorDocument 401</code> directive then it must refer to a local
962 document.</strong></p>
964 <p>Microsoft Internet Explorer (MSIE) will by default ignore
965 server-generated error messages when they are "too small" and substitute
966 its own "friendly" error messages. The size threshold varies depending on
967 the type of error, but in general, if you make your error document
968 greater than 512 bytes, then MSIE will show the server-generated
969 error rather than masking it. More information is available in
970 Microsoft Knowledge Base article <a
971 href="http://support.microsoft.com/default.aspx?scid=kb;en-us;Q294807"
974 <p>Although most error messages can be overriden, there are certain
975 circumstances where the internal messages are used regardless of the
976 setting of <directive module="core">ErrorDocument</directive>. In
977 particular, if a malformed request is detected, normal request processing
978 will be immediately halted and the internal error message returned.
979 This is necessary to guard against security problems caused by
982 <p>Prior to version 2.0, messages were indicated by prefixing
983 them with a single unmatched double quote character.</p>
986 <seealso><a href="../custom-error.html">documentation of
987 customizable responses</a></seealso>
991 <name>ErrorLog</name>
992 <description>Location where the server will log errors</description>
993 <syntax> ErrorLog <var>file-path</var>|syslog[:<var>facility</var>]</syntax>
994 <default>ErrorLog logs/error_log (Unix) ErrorLog logs/error.log (Windows and OS/2)</default>
995 <contextlist><context>server config</context><context>virtual host</context>
999 <p>The <directive>ErrorLog</directive> directive sets the name of
1000 the file to which the server will log any errors it encounters. If
1001 the <var>file-path</var> is not absolute then it is assumed to be
1002 relative to the <directive module="core">ServerRoot</directive>.</p>
1004 <example><title>Example</title>
1005 ErrorLog /var/log/httpd/error_log
1008 <p>If the <var>file-path</var>
1009 begins with a pipe (|) then it is assumed to be a command to spawn
1010 to handle the error log.</p>
1012 <example><title>Example</title>
1013 ErrorLog "|/usr/local/bin/httpd_errors"
1016 <p>Using <code>syslog</code> instead of a filename enables logging
1017 via syslogd(8) if the system supports it. The default is to use
1018 syslog facility <code>local7</code>, but you can override this by
1019 using the <code>syslog:<var>facility</var></code> syntax where
1020 <var>facility</var> can be one of the names usually documented in
1023 <example><title>Example</title>
1024 ErrorLog syslog:user
1027 <p>SECURITY: See the <a
1028 href="../misc/security_tips.html#serverroot">security tips</a>
1029 document for details on why your security could be compromised
1030 if the directory where log files are stored is writable by
1031 anyone other than the user that starts the server.</p>
1032 <note type="warning"><title>Note</title>
1033 <p>When entering a file path on non-Unix platforms, care should be taken
1034 to make sure that only forward slashed are used even though the platform
1035 may allow the use of back slashes. In general it is a good idea to always
1036 use forward slashes throughout the configuration files.</p>
1039 <seealso><directive module="core">LogLevel</directive></seealso>
1040 <seealso><a href="../logs.html">Apache Log Files</a></seealso>
1041 </directivesynopsis>
1044 <name>FileETag</name>
1045 <description>File attributes used to create the ETag
1046 HTTP response header</description>
1047 <syntax>FileETag <var>component</var> ...</syntax>
1048 <default>FileETag INode MTime Size</default>
1049 <contextlist><context>server config</context><context>virtual host</context>
1050 <context>directory</context><context>.htaccess</context>
1052 <override>FileInfo</override>
1056 The <directive>FileETag</directive> directive configures the file
1057 attributes that are used to create the <code>ETag</code> (entity
1058 tag) response header field when the document is based on a file.
1059 (The <code>ETag</code> value is used in cache management to save
1060 network bandwidth.) In Apache 1.3.22 and earlier, the
1061 <code>ETag</code> value was <em>always</em> formed
1062 from the file's inode, size, and last-modified time (mtime). The
1063 <directive>FileETag</directive> directive allows you to choose
1064 which of these -- if any -- should be used. The recognized keywords are:
1068 <dt><strong>INode</strong></dt>
1069 <dd>The file's i-node number will be included in the calculation</dd>
1070 <dt><strong>MTime</strong></dt>
1071 <dd>The date and time the file was last modified will be included</dd>
1072 <dt><strong>Size</strong></dt>
1073 <dd>The number of bytes in the file will be included</dd>
1074 <dt><strong>All</strong></dt>
1075 <dd>All available fields will be used. This is equivalent to:
1076 <example>FileETag INode MTime Size</example></dd>
1077 <dt><strong>None</strong></dt>
1078 <dd>If a document is file-based, no <code>ETag</code> field will be
1079 included in the response</dd>
1082 <p>The <code>INode</code>, <code>MTime</code>, and <code>Size</code>
1083 keywords may be prefixed with either <code>+</code> or <code>-</code>,
1084 which allow changes to be made to the default setting inherited
1085 from a broader scope. Any keyword appearing without such a prefix
1086 immediately and completely cancels the inherited setting.</p>
1088 <p>If a directory's configuration includes
1089 <code>FileETag INode MTime Size</code>, and a
1090 subdirectory's includes <code>FileETag -INode</code>,
1091 the setting for that subdirectory (which will be inherited by
1092 any sub-subdirectories that don't override it) will be equivalent to
1093 <code>FileETag MTime Size</code>.</p>
1095 </directivesynopsis>
1097 <directivesynopsis type="section">
1099 <description>Contains directives that apply to matched
1100 filenames</description>
1101 <syntax><Files <var>filename</var>> ... </Files></syntax>
1102 <contextlist><context>server config</context><context>virtual host</context>
1103 <context>directory</context><context>.htaccess</context>
1105 <override>All</override>
1108 <p>The <directive type="section">Files</directive> directive
1109 limits the scope of the enclosed directives by filename. It is comparable
1110 to the <directive module="core" type="section">Directory</directive>
1111 and <directive module="core" type="section">Location</directive>
1112 directives. It should be matched with a <code></Files></code>
1113 directive. The directives given within this section will be applied to
1114 any object with a basename (last component of filename) matching the
1115 specified filename. <directive type="section">Files</directive>
1116 sections are processed in the order they appear in the
1117 configuration file, after the <directive module="core"
1118 type="section">Directory</directive> sections and
1119 <code>.htaccess</code> files are read, but before <directive
1120 type="section" module="core">Location</directive> sections. Note
1121 that <directive type="section">Files</directive> can be nested
1122 inside <directive type="section"
1123 module="core">Directory</directive> sections to restrict the
1124 portion of the filesystem they apply to.</p>
1126 <p>The <var>filename</var> argument should include a filename, or
1127 a wild-card string, where <code>?</code> matches any single character,
1128 and <code>*</code> matches any sequences of characters.
1129 <glossary ref="regex">Regular expressions</glossary>
1130 can also be used, with the addition of the
1131 <code>~</code> character. For example:</p>
1134 <Files ~ "\.(gif|jpe?g|png)$">
1137 <p>would match most common Internet graphics formats. <directive
1138 module="core" type="section">FilesMatch</directive> is preferred,
1141 <p>Note that unlike <directive type="section"
1142 module="core">Directory</directive> and <directive type="section"
1143 module="core">Location</directive> sections, <directive
1144 type="section">Files</directive> sections can be used inside
1145 <code>.htaccess</code> files. This allows users to control access to
1146 their own files, at a file-by-file level.</p>
1149 <seealso><a href="../sections.html">How <Directory>, <Location>
1150 and <Files> sections work</a> for an explanation of how these
1151 different sections are combined when a request is received</seealso>
1152 </directivesynopsis>
1154 <directivesynopsis type="section">
1155 <name>FilesMatch</name>
1156 <description>Contains directives that apply to regular-expression matched
1157 filenames</description>
1158 <syntax><FilesMatch <var>regex</var>> ... </FilesMatch></syntax>
1159 <contextlist><context>server config</context><context>virtual host</context>
1160 <context>directory</context><context>.htaccess</context>
1162 <override>All</override>
1165 <p>The <directive type="section">FilesMatch</directive> directive
1166 limits the scope of the enclosed directives by filename, just as the
1167 <directive module="core" type="section">Files</directive> directive
1168 does. However, it accepts a <glossary ref="regex">regular
1169 expression</glossary>. For example:</p>
1172 <FilesMatch "\.(gif|jpe?g|png)$">
1175 <p>would match most common Internet graphics formats.</p>
1178 <seealso><a href="../sections.html">How <Directory>, <Location>
1179 and <Files> sections work</a> for an explanation of how these
1180 different sections are combined when a request is received</seealso>
1181 </directivesynopsis>
1184 <name>ForceType</name>
1185 <description>Forces all matching files to be served with the specified
1186 MIME content-type</description>
1187 <syntax>ForceType <var>MIME-type</var>|None</syntax>
1188 <contextlist><context>directory</context><context>.htaccess</context>
1190 <override>FileInfo</override>
1191 <compatibility>Moved to the core in Apache 2.0</compatibility>
1194 <p>When placed into an <code>.htaccess</code> file or a
1195 <directive type="section" module="core">Directory</directive>, or
1196 <directive type="section" module="core">Location</directive> or
1197 <directive type="section" module="core">Files</directive>
1198 section, this directive forces all matching files to be served
1199 with the content type identification given by
1200 <var>MIME-type</var>. For example, if you had a directory full of
1201 GIF files, but did not want to label them all with <code>.gif</code>,
1202 you might want to use:</p>
1208 <p>Note that unlike <directive module="core">DefaultType</directive>,
1209 this directive overrides all mime-type associations, including
1210 filename extensions, that might identify the media type.</p>
1212 <p>You can override any <directive>ForceType</directive> setting
1213 by using the value of <code>None</code>:</p>
1216 # force all files to be image/gif:<br />
1217 <Location /images><br />
1219 ForceType image/gif<br />
1221 </Location><br />
1223 # but normal mime-type associations here:<br />
1224 <Location /images/mixed><br />
1226 ForceType None<br />
1231 </directivesynopsis>
1234 <name>HostnameLookups</name>
1235 <description>Enables DNS lookups on client IP addresses</description>
1236 <syntax>HostnameLookups On|Off|Double</syntax>
1237 <default>HostnameLookups Off</default>
1238 <contextlist><context>server config</context><context>virtual host</context>
1239 <context>directory</context></contextlist>
1242 <p>This directive enables DNS lookups so that host names can be
1243 logged (and passed to CGIs/SSIs in <code>REMOTE_HOST</code>).
1244 The value <code>Double</code> refers to doing double-reverse
1245 DNS lookup. That is, after a reverse lookup is performed, a forward
1246 lookup is then performed on that result. At least one of the IP
1247 addresses in the forward lookup must match the original
1248 address. (In "tcpwrappers" terminology this is called
1249 <code>PARANOID</code>.)</p>
1251 <p>Regardless of the setting, when <module>mod_authz_host</module> is
1252 used for controlling access by hostname, a double reverse lookup
1253 will be performed. This is necessary for security. Note that the
1254 result of this double-reverse isn't generally available unless you
1255 set <code>HostnameLookups Double</code>. For example, if only
1256 <code>HostnameLookups On</code> and a request is made to an object
1257 that is protected by hostname restrictions, regardless of whether
1258 the double-reverse fails or not, CGIs will still be passed the
1259 single-reverse result in <code>REMOTE_HOST</code>.</p>
1261 <p>The default is <code>Off</code> in order to save the network
1262 traffic for those sites that don't truly need the reverse
1263 lookups done. It is also better for the end users because they
1264 don't have to suffer the extra latency that a lookup entails.
1265 Heavily loaded sites should leave this directive
1266 <code>Off</code>, since DNS lookups can take considerable
1267 amounts of time. The utility <program>logresolve</program>, compiled by
1268 default to the <code>bin</code> subdirectory of your installation
1269 directory, can be used to look up host names from logged IP addresses
1272 </directivesynopsis>
1274 <directivesynopsis type="section">
1275 <name>IfDefine</name>
1276 <description>Encloses directives that will be processed only
1277 if a test is true at startup</description>
1278 <syntax><IfDefine [!]<var>parameter-name</var>> ...
1279 </IfDefine></syntax>
1280 <contextlist><context>server config</context><context>virtual host</context>
1281 <context>directory</context><context>.htaccess</context>
1283 <override>All</override>
1286 <p>The <code><IfDefine <var>test</var>>...</IfDefine>
1287 </code> section is used to mark directives that are conditional. The
1288 directives within an <directive type="section">IfDefine</directive>
1289 section are only processed if the <var>test</var> is true. If <var>
1290 test</var> is false, everything between the start and end markers is
1293 <p>The <var>test</var> in the <directive type="section"
1294 >IfDefine</directive> section directive can be one of two forms:</p>
1297 <li><var>parameter-name</var></li>
1299 <li><code>!</code><var>parameter-name</var></li>
1302 <p>In the former case, the directives between the start and end
1303 markers are only processed if the parameter named
1304 <var>parameter-name</var> is defined. The second format reverses
1305 the test, and only processes the directives if
1306 <var>parameter-name</var> is <strong>not</strong> defined.</p>
1308 <p>The <var>parameter-name</var> argument is a define as given on
1309 the <program>httpd</program> command line via <code>-D<var>parameter-</var>
1310 </code>, at the time the server was started.</p>
1312 <p><directive type="section">IfDefine</directive> sections are
1313 nest-able, which can be used to implement simple
1314 multiple-parameter tests. Example:</p>
1317 httpd -DReverseProxy ...<br />
1320 <IfDefine ReverseProxy><br />
1322 LoadModule rewrite_module modules/mod_rewrite.so<br />
1323 LoadModule proxy_module modules/libproxy.so<br />
1328 </directivesynopsis>
1330 <directivesynopsis type="section">
1331 <name>IfModule</name>
1332 <description>Encloses directives that are processed conditional on the
1333 presence or absence of a specific module</description>
1334 <syntax><IfModule [!]<var>module-file</var>|<var>module-identifier</var>> ...
1335 </IfModule></syntax>
1336 <contextlist><context>server config</context><context>virtual host</context>
1337 <context>directory</context><context>.htaccess</context>
1339 <override>All</override>
1340 <compatibility>Module identifiers are available in version 2.1 and
1341 later.</compatibility>
1344 <p>The <code><IfModule <var>test</var>>...</IfModule></code>
1345 section is used to mark directives that are conditional on the presence of
1346 a specific module. The directives within an <directive type="section"
1347 >IfModule</directive> section are only processed if the <var>test</var>
1348 is true. If <var>test</var> is false, everything between the start and
1349 end markers is ignored.</p>
1351 <p>The <var>test</var> in the <directive type="section"
1352 >IfModule</directive> section directive can be one of two forms:</p>
1355 <li><var>module</var></li>
1357 <li>!<var>module</var></li>
1360 <p>In the former case, the directives between the start and end
1361 markers are only processed if the module named <var>module</var>
1362 is included in Apache -- either compiled in or
1363 dynamically loaded using <directive module="mod_so"
1364 >LoadModule</directive>. The second format reverses the test,
1365 and only processes the directives if <var>module</var> is
1366 <strong>not</strong> included.</p>
1368 <p>The <var>module</var> argument can be either the module identifier or
1369 the file name of the module, at the time it was compiled. For example,
1370 <code>rewrite_module</code> is the identifier and
1371 <code>mod_rewrite.c</code> is the file name. If a module consists of
1372 several source files, use the name of the file containing the string
1373 <code>STANDARD20_MODULE_STUFF</code>.</p>
1375 <p><directive type="section">IfModule</directive> sections are
1376 nest-able, which can be used to implement simple multiple-module
1379 <note>This section should only be used if you need to have one
1380 configuration file that works whether or not a specific module
1381 is available. In normal operation, directives need not be
1382 placed in <directive type="section">IfModule</directive>
1385 </directivesynopsis>
1388 <name>Include</name>
1389 <description>Includes other configuration files from within
1390 the server configuration files</description>
1391 <syntax>Include <var>file-path</var>|<var>directory-path</var></syntax>
1392 <contextlist><context>server config</context><context>virtual host</context>
1393 <context>directory</context>
1395 <compatibility>Wildcard matching available in 2.0.41 and later</compatibility>
1398 <p>This directive allows inclusion of other configuration files
1399 from within the server configuration files.</p>
1401 <p>Shell-style (<code>fnmatch()</code>) wildcard characters can be used to
1402 include several files at once, in alphabetical order. In
1403 addition, if <directive>Include</directive> points to a directory,
1404 rather than a file, Apache will read all files in that directory
1405 and any subdirectory. But including entire directories is not
1406 recommended, because it is easy to accidentally leave temporary
1407 files in a directory that can cause <program>httpd</program> to
1410 <p>The file path specified may be an absolute path, or may be relative
1411 to the <directive module="core">ServerRoot</directive> directory.</p>
1416 Include /usr/local/apache2/conf/ssl.conf<br />
1417 Include /usr/local/apache2/conf/vhosts/*.conf
1420 <p>Or, providing paths relative to your <directive
1421 module="core">ServerRoot</directive> directory:</p>
1424 Include conf/ssl.conf<br />
1425 Include conf/vhosts/*.conf
1428 <p>Running <code>apachectl configtest</code> will give you a list
1429 of the files that are being processed during the configuration
1433 root@host# apachectl configtest<br />
1434 Processing config file: /usr/local/apache2/conf/ssl.conf<br />
1435 Processing config file: /usr/local/apache2/conf/vhosts/vhost1.conf<br />
1436 Processing config file: /usr/local/apache2/conf/vhosts/vhost2.conf<br />
1441 <seealso><program>apachectl</program></seealso>
1442 </directivesynopsis>
1445 <name>KeepAlive</name>
1446 <description>Enables HTTP persistent connections</description>
1447 <syntax>KeepAlive On|Off</syntax>
1448 <default>KeepAlive On</default>
1449 <contextlist><context>server config</context><context>virtual host</context>
1453 <p>The Keep-Alive extension to HTTP/1.0 and the persistent
1454 connection feature of HTTP/1.1 provide long-lived HTTP sessions
1455 which allow multiple requests to be sent over the same TCP
1456 connection. In some cases this has been shown to result in an
1457 almost 50% speedup in latency times for HTML documents with
1458 many images. To enable Keep-Alive connections, set
1459 <code>KeepAlive On</code>.</p>
1461 <p>For HTTP/1.0 clients, Keep-Alive connections will only be
1462 used if they are specifically requested by a client. In
1463 addition, a Keep-Alive connection with an HTTP/1.0 client can
1464 only be used when the length of the content is known in
1465 advance. This implies that dynamic content such as CGI output,
1466 SSI pages, and server-generated directory listings will
1467 generally not use Keep-Alive connections to HTTP/1.0 clients.
1468 For HTTP/1.1 clients, persistent connections are the default
1469 unless otherwise specified. If the client requests it, chunked
1470 encoding will be used in order to send content of unknown
1471 length over persistent connections.</p>
1473 <p>When a client uses a Keep-Alive connection it will be counted
1474 as a single "request" for the MaxRequestsPerChild directive, regardless
1475 of how many requests are sent using the connection.</p>
1478 <seealso><directive module="core">MaxKeepAliveRequests</directive></seealso>
1479 </directivesynopsis>
1482 <name>KeepAliveTimeout</name>
1483 <description>Amount of time the server will wait for subsequent
1484 requests on a persistent connection</description>
1485 <syntax>KeepAliveTimeout <var>seconds</var></syntax>
1486 <default>KeepAliveTimeout 5</default>
1487 <contextlist><context>server config</context><context>virtual host</context>
1491 <p>The number of seconds Apache will wait for a subsequent
1492 request before closing the connection. Once a request has been
1493 received, the timeout value specified by the
1494 <directive module="core">Timeout</directive> directive applies.</p>
1496 <p>Setting <directive>KeepAliveTimeout</directive> to a high value
1497 may cause performance problems in heavily loaded servers. The
1498 higher the timeout, the more server processes will be kept
1499 occupied waiting on connections with idle clients.</p>
1501 </directivesynopsis>
1503 <directivesynopsis type="section">
1505 <description>Restrict enclosed access controls to only certain HTTP
1506 methods</description>
1507 <syntax><Limit <var>method</var> [<var>method</var>] ... > ...
1508 </Limit></syntax>
1509 <contextlist><context>server config</context><context>virtual host</context>
1510 <context>directory</context><context>.htaccess</context>
1512 <override>All</override>
1515 <p>Access controls are normally effective for
1516 <strong>all</strong> access methods, and this is the usual
1517 desired behavior. <strong>In the general case, access control
1518 directives should not be placed within a
1519 <directive type="section">Limit</directive> section.</strong></p>
1521 <p>The purpose of the <directive type="section">Limit</directive>
1522 directive is to restrict the effect of the access controls to the
1523 nominated HTTP methods. For all other methods, the access
1524 restrictions that are enclosed in the <directive
1525 type="section">Limit</directive> bracket <strong>will have no
1526 effect</strong>. The following example applies the access control
1527 only to the methods <code>POST</code>, <code>PUT</code>, and
1528 <code>DELETE</code>, leaving all other methods unprotected:</p>
1531 <Limit POST PUT DELETE><br />
1533 Require valid-user<br />
1538 <p>The method names listed can be one or more of: <code>GET</code>,
1539 <code>POST</code>, <code>PUT</code>, <code>DELETE</code>,
1540 <code>CONNECT</code>, <code>OPTIONS</code>,
1541 <code>PATCH</code>, <code>PROPFIND</code>, <code>PROPPATCH</code>,
1542 <code>MKCOL</code>, <code>COPY</code>, <code>MOVE</code>,
1543 <code>LOCK</code>, and <code>UNLOCK</code>. <strong>The method name is
1544 case-sensitive.</strong> If <code>GET</code> is used it will also
1545 restrict <code>HEAD</code> requests. The <code>TRACE</code> method
1546 cannot be limited.</p>
1548 <note type="warning">A <directive type="section"
1549 module="core">LimitExcept</directive> section should always be
1550 used in preference to a <directive type="section"
1551 module="core">Limit</directive> section when restricting access,
1552 since a <directive type="section"
1553 module="core">LimitExcept</directive> section provides protection
1554 against arbitrary methods.</note>
1557 </directivesynopsis>
1559 <directivesynopsis type="section">
1560 <name>LimitExcept</name>
1561 <description>Restrict access controls to all HTTP methods
1562 except the named ones</description>
1563 <syntax><LimitExcept <var>method</var> [<var>method</var>] ... > ...
1564 </LimitExcept></syntax>
1565 <contextlist><context>server config</context><context>virtual host</context>
1566 <context>directory</context><context>.htaccess</context>
1568 <override>All</override>
1571 <p><directive type="section">LimitExcept</directive> and
1572 <code></LimitExcept></code> are used to enclose
1573 a group of access control directives which will then apply to any
1574 HTTP access method <strong>not</strong> listed in the arguments;
1575 i.e., it is the opposite of a <directive type="section"
1576 module="core">Limit</directive> section and can be used to control
1577 both standard and nonstandard/unrecognized methods. See the
1578 documentation for <directive module="core"
1579 type="section">Limit</directive> for more details.</p>
1584 <LimitExcept POST GET><br />
1586 Require valid-user<br />
1588 </LimitExcept>
1592 </directivesynopsis>
1595 <name>LimitInternalRecursion</name>
1596 <description>Determine maximum number of internal redirects and nested
1597 subrequests</description>
1598 <syntax>LimitInternalRecursion <var>number</var> [<var>number</var>]</syntax>
1599 <default>LimitInternalRecursion 10</default>
1600 <contextlist><context>server config</context><context>virtual host</context>
1602 <compatibility>Available in Apache 2.0.47 and later</compatibility>
1605 <p>An internal redirect happens, for example, when using the <directive
1606 module="mod_actions">Action</directive> directive, which internally
1607 redirects the original request to a CGI script. A subrequest is Apache's
1608 mechanism to find out what would happen for some URI if it were requested.
1609 For example, <module>mod_dir</module> uses subrequests to look for the
1610 files listed in the <directive module="mod_dir">DirectoryIndex</directive>
1613 <p><directive>LimitInternalRecursion</directive> prevents the server
1614 from crashing when entering an infinite loop of internal redirects or
1615 subrequests. Such loops are usually caused by misconfigurations.</p>
1617 <p>The directive stores two different limits, which are evaluated on
1618 per-request basis. The first <var>number</var> is the maximum number of
1619 internal redirects, that may follow each other. The second <var>number</var>
1620 determines, how deep subrequests may be nested. If you specify only one
1621 <var>number</var>, it will be assigned to both limits.</p>
1623 <example><title>Example</title>
1624 LimitInternalRecursion 5
1627 </directivesynopsis>
1630 <name>LimitRequestBody</name>
1631 <description>Restricts the total size of the HTTP request body sent
1632 from the client</description>
1633 <syntax>LimitRequestBody <var>bytes</var></syntax>
1634 <default>LimitRequestBody 0</default>
1635 <contextlist><context>server config</context><context>virtual host</context>
1636 <context>directory</context><context>.htaccess</context>
1638 <override>All</override>
1641 <p>This directive specifies the number of <var>bytes</var> from 0
1642 (meaning unlimited) to 2147483647 (2GB) that are allowed in a
1645 <p>The <directive>LimitRequestBody</directive> directive allows
1646 the user to set a limit on the allowed size of an HTTP request
1647 message body within the context in which the directive is given
1648 (server, per-directory, per-file or per-location). If the client
1649 request exceeds that limit, the server will return an error
1650 response instead of servicing the request. The size of a normal
1651 request message body will vary greatly depending on the nature of
1652 the resource and the methods allowed on that resource. CGI scripts
1653 typically use the message body for retrieving form information.
1654 Implementations of the <code>PUT</code> method will require
1655 a value at least as large as any representation that the server
1656 wishes to accept for that resource.</p>
1658 <p>This directive gives the server administrator greater
1659 control over abnormal client request behavior, which may be
1660 useful for avoiding some forms of denial-of-service
1663 <p>If, for example, you are permitting file upload to a particular
1664 location, and wish to limit the size of the uploaded file to 100K,
1665 you might use the following directive:</p>
1668 LimitRequestBody 102400
1672 </directivesynopsis>
1675 <name>LimitRequestFields</name>
1676 <description>Limits the number of HTTP request header fields that
1677 will be accepted from the client</description>
1678 <syntax>LimitRequestFields <var>number</var></syntax>
1679 <default>LimitRequestFields 100</default>
1680 <contextlist><context>server config</context></contextlist>
1683 <p><var>Number</var> is an integer from 0 (meaning unlimited) to
1684 32767. The default value is defined by the compile-time
1685 constant <code>DEFAULT_LIMIT_REQUEST_FIELDS</code> (100 as
1688 <p>The <directive>LimitRequestFields</directive> directive allows
1689 the server administrator to modify the limit on the number of
1690 request header fields allowed in an HTTP request. A server needs
1691 this value to be larger than the number of fields that a normal
1692 client request might include. The number of request header fields
1693 used by a client rarely exceeds 20, but this may vary among
1694 different client implementations, often depending upon the extent
1695 to which a user has configured their browser to support detailed
1696 content negotiation. Optional HTTP extensions are often expressed
1697 using request header fields.</p>
1699 <p>This directive gives the server administrator greater
1700 control over abnormal client request behavior, which may be
1701 useful for avoiding some forms of denial-of-service attacks.
1702 The value should be increased if normal clients see an error
1703 response from the server that indicates too many fields were
1704 sent in the request.</p>
1709 LimitRequestFields 50
1713 </directivesynopsis>
1716 <name>LimitRequestFieldSize</name>
1717 <description>Limits the size of the HTTP request header allowed from the
1718 client</description>
1719 <syntax>LimitRequestFieldsize <var>bytes</var></syntax>
1720 <default>LimitRequestFieldsize 8190</default>
1721 <contextlist><context>server config</context></contextlist>
1724 <p>This directive specifies the number of <var>bytes</var>
1725 that will be allowed in an HTTP request header.</p>
1727 <p>The <directive>LimitRequestFieldSize</directive> directive
1728 allows the server administrator to reduce or increase the limit
1729 on the allowed size of an HTTP request header field. A server
1730 needs this value to be large enough to hold any one header field
1731 from a normal client request. The size of a normal request header
1732 field will vary greatly among different client implementations,
1733 often depending upon the extent to which a user has configured
1734 their browser to support detailed content negotiation. SPNEGO
1735 authentication headers can be up to 12392 bytes.</p>
1737 <p>This directive gives the server administrator greater
1738 control over abnormal client request behavior, which may be
1739 useful for avoiding some forms of denial-of-service attacks.</p>
1744 LimitRequestFieldSize 4094
1747 <note>Under normal conditions, the value should not be changed from
1751 </directivesynopsis>
1754 <name>LimitRequestLine</name>
1755 <description>Limit the size of the HTTP request line that will be accepted
1756 from the client</description>
1757 <syntax>LimitRequestLine <var>bytes</var></syntax>
1758 <default>LimitRequestLine 8190</default>
1759 <contextlist><context>server config</context></contextlist>
1762 <p>This directive sets the number of <var>bytes</var> that will be
1763 allowed on the HTTP request-line.</p>
1765 <p>The <directive>LimitRequestLine</directive> directive allows
1766 the server administrator to reduce or increase the limit on the allowed size
1767 of a client's HTTP request-line. Since the request-line consists of the
1768 HTTP method, URI, and protocol version, the
1769 <directive>LimitRequestLine</directive> directive places a
1770 restriction on the length of a request-URI allowed for a request
1771 on the server. A server needs this value to be large enough to
1772 hold any of its resource names, including any information that
1773 might be passed in the query part of a <code>GET</code> request.</p>
1775 <p>This directive gives the server administrator greater
1776 control over abnormal client request behavior, which may be
1777 useful for avoiding some forms of denial-of-service attacks.</p>
1782 LimitRequestLine 4094
1785 <note>Under normal conditions, the value should not be changed from
1788 </directivesynopsis>
1791 <name>LimitXMLRequestBody</name>
1792 <description>Limits the size of an XML-based request body</description>
1793 <syntax>LimitXMLRequestBody <var>bytes</var></syntax>
1794 <default>LimitXMLRequestBody 1000000</default>
1795 <contextlist><context>server config</context><context>virtual host</context>
1796 <context>directory</context><context>.htaccess</context></contextlist>
1797 <override>All</override>
1800 <p>Limit (in bytes) on maximum size of an XML-based request
1801 body. A value of <code>0</code> will disable any checking.</p>
1806 LimitXMLRequestBody 0
1810 </directivesynopsis>
1812 <directivesynopsis type="section">
1813 <name>Location</name>
1814 <description>Applies the enclosed directives only to matching
1816 <syntax><Location
1817 <var>URL-path</var>|<var>URL</var>> ... </Location></syntax>
1818 <contextlist><context>server config</context><context>virtual host</context>
1822 <p>The <directive type="section">Location</directive> directive
1823 limits the scope of the enclosed directives by URL. It is similar to the
1824 <directive type="section" module="core">Directory</directive>
1825 directive, and starts a subsection which is terminated with a
1826 <code></Location></code> directive. <directive
1827 type="section">Location</directive> sections are processed in the
1828 order they appear in the configuration file, after the <directive
1829 type="section" module="core">Directory</directive> sections and
1830 <code>.htaccess</code> files are read, and after the <directive
1831 type="section" module="core">Files</directive> sections.</p>
1833 <p><directive type="section">Location</directive> sections operate
1834 completely outside the filesystem. This has several consequences.
1835 Most importantly, <directive type="section">Location</directive>
1836 directives should not be used to control access to filesystem
1837 locations. Since several different URLs may map to the same
1838 filesystem location, such access controls may by circumvented.</p>
1840 <note><title>When to use <directive
1841 type="section">Location</directive></title>
1843 <p>Use <directive type="section">Location</directive> to apply
1844 directives to content that lives outside the filesystem. For
1845 content that lives in the filesystem, use <directive
1846 type="section" module="core">Directory</directive> and <directive
1847 type="section" module="core">Files</directive>. An exception is
1848 <code><Location /></code>, which is an easy way to
1849 apply a configuration to the entire server.</p>
1852 <p>For all origin (non-proxy) requests, the URL to be matched is a
1853 URL-path of the form <code>/path/</code>. No scheme, hostname,
1854 port, or query string may be included. For proxy requests, the
1855 URL to be matched is of the form
1856 <code>scheme://servername/path</code>, and you must include the
1859 <p>The URL may use wildcards. In a wild-card string, <code>?</code> matches
1860 any single character, and <code>*</code> matches any sequences of
1863 <p><glossary ref="regex">Regular expressions</glossary>
1864 can also be used, with the addition of the
1865 <code>~</code> character. For example:</p>
1868 <Location ~ "/(extra|special)/data">
1871 <p>would match URLs that contained the substring <code>/extra/data</code>
1872 or <code>/special/data</code>. The directive <directive
1873 type="section" module="core">LocationMatch</directive> behaves
1874 identical to the regex version of <directive
1875 type="section">Location</directive>.</p>
1877 <p>The <directive type="section">Location</directive>
1878 functionality is especially useful when combined with the
1879 <directive module="core">SetHandler</directive>
1880 directive. For example, to enable status requests, but allow them
1881 only from browsers at <code>foo.com</code>, you might use:</p>
1884 <Location /status><br />
1886 SetHandler server-status<br />
1887 Order Deny,Allow<br />
1889 Allow from .foo.com<br />
1894 <note><title>Note about / (slash)</title>
1895 <p>The slash character has special meaning depending on where in a
1896 URL it appears. People may be used to its behavior in the filesystem
1897 where multiple adjacent slashes are frequently collapsed to a single
1898 slash (<em>i.e.</em>, <code>/home///foo</code> is the same as
1899 <code>/home/foo</code>). In URL-space this is not necessarily true.
1900 The <directive type="section" module="core">LocationMatch</directive>
1901 directive and the regex version of <directive type="section"
1902 >Location</directive> require you to explicitly specify multiple
1903 slashes if that is your intention.</p>
1905 <p>For example, <code><LocationMatch ^/abc></code> would match
1906 the request URL <code>/abc</code> but not the request URL <code>
1907 //abc</code>. The (non-regex) <directive type="section"
1908 >Location</directive> directive behaves similarly when used for
1909 proxy requests. But when (non-regex) <directive type="section"
1910 >Location</directive> is used for non-proxy requests it will
1911 implicitly match multiple slashes with a single slash. For example,
1912 if you specify <code><Location /abc/def></code> and the
1913 request is to <code>/abc//def</code> then it will match.</p>
1916 <seealso><a href="../sections.html">How <Directory>, <Location>
1917 and <Files> sections work</a> for an explanation of how these
1918 different sections are combined when a request is received</seealso>
1919 </directivesynopsis>
1921 <directivesynopsis type="section">
1922 <name>LocationMatch</name>
1923 <description>Applies the enclosed directives only to regular-expression
1924 matching URLs</description>
1925 <syntax><LocationMatch
1926 <var>regex</var>> ... </LocationMatch></syntax>
1927 <contextlist><context>server config</context><context>virtual host</context>
1931 <p>The <directive type="section">LocationMatch</directive> directive
1932 limits the scope of the enclosed directives by URL, in an identical manner
1933 to <directive module="core" type="section">Location</directive>. However,
1934 it takes a <glossary ref="regex">regular expression</glossary>
1935 as an argument instead of a simple string. For example:</p>
1938 <LocationMatch "/(extra|special)/data">
1941 <p>would match URLs that contained the substring <code>/extra/data</code>
1942 or <code>/special/data</code>.</p>
1945 <seealso><a href="../sections.html">How <Directory>, <Location>
1946 and <Files> sections work</a> for an explanation of how these
1947 different sections are combined when a request is received</seealso>
1948 </directivesynopsis>
1951 <name>LogLevel</name>
1952 <description>Controls the verbosity of the ErrorLog</description>
1953 <syntax>LogLevel <var>level</var></syntax>
1954 <default>LogLevel warn</default>
1955 <contextlist><context>server config</context><context>virtual host</context>
1959 <p><directive>LogLevel</directive> adjusts the verbosity of the
1960 messages recorded in the error logs (see <directive
1961 module="core">ErrorLog</directive> directive). The following
1962 <var>level</var>s are available, in order of decreasing
1966 <columnspec><column width=".2"/><column width=".3"/><column width=".5"/>
1969 <th><strong>Level</strong> </th>
1971 <th><strong>Description</strong> </th>
1973 <th><strong>Example</strong> </th>
1977 <td><code>emerg</code> </td>
1979 <td>Emergencies - system is unusable.</td>
1981 <td>"Child cannot open lock file. Exiting"</td>
1985 <td><code>alert</code> </td>
1987 <td>Action must be taken immediately.</td>
1989 <td>"getpwuid: couldn't determine user name from uid"</td>
1993 <td><code>crit</code> </td>
1995 <td>Critical Conditions.</td>
1997 <td>"socket: Failed to get a socket, exiting child"</td>
2001 <td><code>error</code> </td>
2003 <td>Error conditions.</td>
2005 <td>"Premature end of script headers"</td>
2009 <td><code>warn</code> </td>
2011 <td>Warning conditions.</td>
2013 <td>"child process 1234 did not exit, sending another
2018 <td><code>notice</code> </td>
2020 <td>Normal but significant condition.</td>
2022 <td>"httpd: caught SIGBUS, attempting to dump core in
2027 <td><code>info</code> </td>
2029 <td>Informational.</td>
2031 <td>"Server seems busy, (you may need to increase
2032 StartServers, or Min/MaxSpareServers)..."</td>
2036 <td><code>debug</code> </td>
2038 <td>Debug-level messages</td>
2040 <td>"Opening config file ..."</td>
2044 <p>When a particular level is specified, messages from all
2045 other levels of higher significance will be reported as well.
2046 <em>E.g.</em>, when <code>LogLevel info</code> is specified,
2047 then messages with log levels of <code>notice</code> and
2048 <code>warn</code> will also be posted.</p>
2050 <p>Using a level of at least <code>crit</code> is
2059 <note><title>Note</title>
2060 <p>When logging to a regular file messages of the level
2061 <code>notice</code> cannot be suppressed and thus are always
2062 logged. However, this doesn't apply when logging is done
2063 using <code>syslog</code>.</p>
2066 </directivesynopsis>
2069 <name>MaxKeepAliveRequests</name>
2070 <description>Number of requests allowed on a persistent
2071 connection</description>
2072 <syntax>MaxKeepAliveRequests <var>number</var></syntax>
2073 <default>MaxKeepAliveRequests 100</default>
2074 <contextlist><context>server config</context><context>virtual host</context>
2078 <p>The <directive>MaxKeepAliveRequests</directive> directive
2079 limits the number of requests allowed per connection when
2080 <directive module="core" >KeepAlive</directive> is on. If it is
2081 set to <code>0</code>, unlimited requests will be allowed. We
2082 recommend that this setting be kept to a high value for maximum
2083 server performance.</p>
2088 MaxKeepAliveRequests 500
2091 </directivesynopsis>
2094 <name>NameVirtualHost</name>
2095 <description>Designates an IP address for name-virtual
2096 hosting</description>
2097 <syntax>NameVirtualHost <var>addr</var>[:<var>port</var>]</syntax>
2098 <contextlist><context>server config</context></contextlist>
2101 <p>The <directive>NameVirtualHost</directive> directive is a
2102 required directive if you want to configure <a
2103 href="../vhosts/">name-based virtual hosts</a>.</p>
2105 <p>Although <var>addr</var> can be hostname it is recommended
2106 that you always use an IP address, e.g.</p>
2109 NameVirtualHost 111.22.33.44
2112 <p>With the <directive>NameVirtualHost</directive> directive you
2113 specify the IP address on which the server will receive requests
2114 for the name-based virtual hosts. This will usually be the address
2115 to which your name-based virtual host names resolve. In cases
2116 where a firewall or other proxy receives the requests and forwards
2117 them on a different IP address to the server, you must specify the
2118 IP address of the physical interface on the machine which will be
2119 servicing the requests. If you have multiple name-based hosts on
2120 multiple addresses, repeat the directive for each address.</p>
2122 <note><title>Note</title>
2123 <p>Note, that the "main server" and any <code>_default_</code> servers
2124 will <strong>never</strong> be served for a request to a
2125 <directive>NameVirtualHost</directive> IP address (unless for some
2126 reason you specify <directive>NameVirtualHost</directive> but then
2127 don't define any <directive>VirtualHost</directive>s for that
2131 <p>Optionally you can specify a port number on which the
2132 name-based virtual hosts should be used, e.g.</p>
2135 NameVirtualHost 111.22.33.44:8080
2138 <p>IPv6 addresses must be enclosed in square brackets, as shown
2139 in the following example:</p>
2142 NameVirtualHost [2001:db8::a00:20ff:fea7:ccea]:8080
2145 <p>To receive requests on all interfaces, you can use an argument of
2152 <note><title>Argument to <directive type="section">VirtualHost</directive>
2154 <p>Note that the argument to the <directive
2155 type="section">VirtualHost</directive> directive must
2156 exactly match the argument to the <directive
2157 >NameVirtualHost</directive> directive.</p>
2160 NameVirtualHost 1.2.3.4<br />
2161 <VirtualHost 1.2.3.4><br />
2163 </VirtualHost><br />
2168 <seealso><a href="../vhosts/">Virtual Hosts
2169 documentation</a></seealso>
2171 </directivesynopsis>
2174 <name>Options</name>
2175 <description>Configures what features are available in a particular
2176 directory</description>
2178 [+|-]<var>option</var> [[+|-]<var>option</var>] ...</syntax>
2179 <default>Options All</default>
2180 <contextlist><context>server config</context><context>virtual host</context>
2181 <context>directory</context><context>.htaccess</context>
2183 <override>Options</override>
2186 <p>The <directive>Options</directive> directive controls which
2187 server features are available in a particular directory.</p>
2189 <p><var>option</var> can be set to <code>None</code>, in which
2190 case none of the extra features are enabled, or one or more of
2194 <dt><code>All</code></dt>
2196 <dd>All options except for <code>MultiViews</code>. This is the default
2199 <dt><code>ExecCGI</code></dt>
2202 Execution of CGI scripts using <module>mod_cgi</module>
2205 <dt><code>FollowSymLinks</code></dt>
2209 The server will follow symbolic links in this directory.
2211 <p>Even though the server follows the symlink it does <em>not</em>
2212 change the pathname used to match against <directive type="section"
2213 module="core">Directory</directive> sections.</p>
2214 <p>Note also, that this option <strong>gets ignored</strong> if set
2215 inside a <directive type="section" module="core">Location</directive>
2219 <dt><code>Includes</code></dt>
2222 Server-side includes provided by <module>mod_include</module>
2225 <dt><code>IncludesNOEXEC</code></dt>
2229 Server-side includes are permitted, but the <code>#exec
2230 cmd</code> and <code>#exec cgi</code> are disabled. It is still
2231 possible to <code>#include virtual</code> CGI scripts from
2232 <directive module="mod_alias">ScriptAlias</directive>ed
2235 <dt><code>Indexes</code></dt>
2238 If a URL which maps to a directory is requested, and there
2239 is no <directive module="mod_dir">DirectoryIndex</directive>
2240 (<em>e.g.</em>, <code>index.html</code>) in that directory, then
2241 <module>mod_autoindex</module> will return a formatted listing
2242 of the directory.</dd>
2244 <dt><code>MultiViews</code></dt>
2247 <a href="../content-negotiation.html">Content negotiated</a>
2248 "MultiViews" are allowed using
2249 <module>mod_negotiation</module>.</dd>
2251 <dt><code>SymLinksIfOwnerMatch</code></dt>
2253 <dd>The server will only follow symbolic links for which the
2254 target file or directory is owned by the same user id as the
2257 <note><title>Note</title> This option gets ignored if
2258 set inside a <directive module="core"
2259 type="section">Location</directive> section.</note>
2263 <p>Normally, if multiple <directive>Options</directive> could
2264 apply to a directory, then the most specific one is used and
2265 others are ignored; the options are not merged. (See <a
2266 href="../sections.html#mergin">how sections are merged</a>.)
2267 However if <em>all</em> the options on the
2268 <directive>Options</directive> directive are preceded by a
2269 <code>+</code> or <code>-</code> symbol, the options are
2270 merged. Any options preceded by a <code>+</code> are added to the
2271 options currently in force, and any options preceded by a
2272 <code>-</code> are removed from the options currently in
2275 <note type="warning"><title>Warning</title>
2276 <p>Mixing <directive>Options</directive> with a <code>+</code> or
2277 <code>-</code> with those without is not valid syntax, and is likely
2278 to cause unexpected results.</p>
2281 <p>For example, without any <code>+</code> and <code>-</code> symbols:</p>
2284 <Directory /web/docs><br />
2286 Options Indexes FollowSymLinks<br />
2288 </Directory><br />
2290 <Directory /web/docs/spec><br />
2292 Options Includes<br />
2297 <p>then only <code>Includes</code> will be set for the
2298 <code>/web/docs/spec</code> directory. However if the second
2299 <directive>Options</directive> directive uses the <code>+</code> and
2300 <code>-</code> symbols:</p>
2303 <Directory /web/docs><br />
2305 Options Indexes FollowSymLinks<br />
2307 </Directory><br />
2309 <Directory /web/docs/spec><br />
2311 Options +Includes -Indexes<br />
2316 <p>then the options <code>FollowSymLinks</code> and
2317 <code>Includes</code> are set for the <code>/web/docs/spec</code>
2320 <note><title>Note</title>
2321 <p>Using <code>-IncludesNOEXEC</code> or
2322 <code>-Includes</code> disables server-side includes completely
2323 regardless of the previous setting.</p>
2326 <p>The default in the absence of any other settings is
2327 <code>All</code>.</p>
2329 </directivesynopsis>
2332 <name>RLimitCPU</name>
2333 <description>Limits the CPU consumption of processes launched
2334 by Apache children</description>
2335 <syntax>RLimitCPU <var>seconds</var>|max [<var>seconds</var>|max]</syntax>
2336 <default>Unset; uses operating system defaults</default>
2337 <contextlist><context>server config</context><context>virtual host</context>
2338 <context>directory</context><context>.htaccess</context></contextlist>
2339 <override>All</override>
2342 <p>Takes 1 or 2 parameters. The first parameter sets the soft
2343 resource limit for all processes and the second parameter sets
2344 the maximum resource limit. Either parameter can be a number,
2345 or <code>max</code> to indicate to the server that the limit should
2346 be set to the maximum allowed by the operating system
2347 configuration. Raising the maximum resource limit requires that
2348 the server is running as <code>root</code>, or in the initial startup
2351 <p>This applies to processes forked off from Apache children
2352 servicing requests, not the Apache children themselves. This
2353 includes CGI scripts and SSI exec commands, but not any
2354 processes forked off from the Apache parent such as piped
2357 <p>CPU resource limits are expressed in seconds per
2360 <seealso><directive module="core">RLimitMEM</directive></seealso>
2361 <seealso><directive module="core">RLimitNPROC</directive></seealso>
2362 </directivesynopsis>
2365 <name>RLimitMEM</name>
2366 <description>Limits the memory consumption of processes launched
2367 by Apache children</description>
2368 <syntax>RLimitMEM <var>bytes</var>|max [<var>bytes</var>|max]</syntax>
2369 <default>Unset; uses operating system defaults</default>
2370 <contextlist><context>server config</context><context>virtual host</context>
2371 <context>directory</context><context>.htaccess</context></contextlist>
2372 <override>All</override>
2375 <p>Takes 1 or 2 parameters. The first parameter sets the soft
2376 resource limit for all processes and the second parameter sets
2377 the maximum resource limit. Either parameter can be a number,
2378 or <code>max</code> to indicate to the server that the limit should
2379 be set to the maximum allowed by the operating system
2380 configuration. Raising the maximum resource limit requires that
2381 the server is running as <code>root</code>, or in the initial startup
2384 <p>This applies to processes forked off from Apache children
2385 servicing requests, not the Apache children themselves. This
2386 includes CGI scripts and SSI exec commands, but not any
2387 processes forked off from the Apache parent such as piped
2390 <p>Memory resource limits are expressed in bytes per
2393 <seealso><directive module="core">RLimitCPU</directive></seealso>
2394 <seealso><directive module="core">RLimitNPROC</directive></seealso>
2395 </directivesynopsis>
2398 <name>RLimitNPROC</name>
2399 <description>Limits the number of processes that can be launched by
2400 processes launched by Apache children</description>
2401 <syntax>RLimitNPROC <var>number</var>|max [<var>number</var>|max]</syntax>
2402 <default>Unset; uses operating system defaults</default>
2403 <contextlist><context>server config</context><context>virtual host</context>
2404 <context>directory</context><context>.htaccess</context></contextlist>
2405 <override>All</override>
2408 <p>Takes 1 or 2 parameters. The first parameter sets the soft
2409 resource limit for all processes and the second parameter sets
2410 the maximum resource limit. Either parameter can be a number,
2411 or <code>max</code> to indicate to the server that the limit
2412 should be set to the maximum allowed by the operating system
2413 configuration. Raising the maximum resource limit requires that
2414 the server is running as <code>root</code>, or in the initial startup
2417 <p>This applies to processes forked off from Apache children
2418 servicing requests, not the Apache children themselves. This
2419 includes CGI scripts and SSI exec commands, but not any
2420 processes forked off from the Apache parent such as piped
2423 <p>Process limits control the number of processes per user.</p>
2425 <note><title>Note</title>
2426 <p>If CGI processes are <strong>not</strong> running
2427 under user ids other than the web server user id, this directive
2428 will limit the number of processes that the server itself can
2429 create. Evidence of this situation will be indicated by
2430 <strong><code>cannot fork</code></strong> messages in the
2431 <code>error_log</code>.</p>
2434 <seealso><directive module="core">RLimitMEM</directive></seealso>
2435 <seealso><directive module="core">RLimitCPU</directive></seealso>
2436 </directivesynopsis>
2439 <name>ScriptInterpreterSource</name>
2440 <description>Technique for locating the interpreter for CGI
2441 scripts</description>
2442 <syntax>ScriptInterpreterSource Registry|Registry-Strict|Script</syntax>
2443 <default>ScriptInterpreterSource Script</default>
2444 <contextlist><context>server config</context><context>virtual host</context>
2445 <context>directory</context><context>.htaccess</context></contextlist>
2446 <override>FileInfo</override>
2447 <compatibility>Win32 only;
2448 option <code>Registry-Strict</code> is available in Apache 2.0 and
2449 later</compatibility>
2452 <p>This directive is used to control how Apache finds the
2453 interpreter used to run CGI scripts. The default setting is
2454 <code>Script</code>. This causes Apache to use the interpreter pointed to
2455 by the shebang line (first line, starting with <code>#!</code>) in the
2456 script. On Win32 systems this line usually looks like:</p>
2459 #!C:/Perl/bin/perl.exe
2462 <p>or, if <code>perl</code> is in the <code>PATH</code>, simply:</p>
2468 <p>Setting <code>ScriptInterpreterSource Registry</code> will
2469 cause the Windows Registry tree <code>HKEY_CLASSES_ROOT</code> to be
2470 searched using the script file extension (e.g., <code>.pl</code>) as a
2471 search key. The command defined by the registry subkey
2472 <code>Shell\ExecCGI\Command</code> or, if it does not exist, by the subkey
2473 <code>Shell\Open\Command</code> is used to open the script file. If the
2474 registry keys cannot be found, Apache falls back to the behavior of the
2475 <code>Script</code> option.</p>
2477 <note type="warning"><title>Security</title>
2478 <p>Be careful when using <code>ScriptInterpreterSource
2479 Registry</code> with <directive
2480 module="mod_alias">ScriptAlias</directive>'ed directories, because
2481 Apache will try to execute <strong>every</strong> file within this
2482 directory. The <code>Registry</code> setting may cause undesired
2483 program calls on files which are typically not executed. For
2484 example, the default open command on <code>.htm</code> files on
2485 most Windows systems will execute Microsoft Internet Explorer, so
2486 any HTTP request for an <code>.htm</code> file existing within the
2487 script directory would start the browser in the background on the
2488 server. This is a good way to crash your system within a minute or
2492 <p>The option <code>Registry-Strict</code> which is new in Apache
2493 2.0 does the same thing as <code>Registry</code> but uses only the
2494 subkey <code>Shell\ExecCGI\Command</code>. The
2495 <code>ExecCGI</code> key is not a common one. It must be
2496 configured manually in the windows registry and hence prevents
2497 accidental program calls on your system.</p>
2499 </directivesynopsis>
2502 <name>ServerAdmin</name>
2503 <description>Email address that the server includes in error
2504 messages sent to the client</description>
2505 <syntax>ServerAdmin <var>email-address</var>|<var>URL</var></syntax>
2506 <contextlist><context>server config</context><context>virtual host</context>
2510 <p>The <directive>ServerAdmin</directive> sets the contact address
2511 that the server includes in any error messages it returns to the
2512 client. If the <code>httpd</code> doesn't recognize the supplied argument
2514 assumes, that it's an <var>email-address</var> and prepends it with
2515 <code>mailto:</code> in hyperlink targets. However, it's recommended to
2516 actually use an email address, since there are a lot of CGI scripts that
2517 make that assumption. If you want to use an URL, it should point to another
2518 server under your control. Otherwise users may not be able to contact you in
2521 <p>It may be worth setting up a dedicated address for this, e.g.</p>
2524 ServerAdmin www-admin@foo.example.com
2526 <p>as users do not always mention that they are talking about the
2529 </directivesynopsis>
2532 <name>ServerAlias</name>
2533 <description>Alternate names for a host used when matching requests
2534 to name-virtual hosts</description>
2535 <syntax>ServerAlias <var>hostname</var> [<var>hostname</var>] ...</syntax>
2536 <contextlist><context>virtual host</context></contextlist>
2539 <p>The <directive>ServerAlias</directive> directive sets the
2540 alternate names for a host, for use with <a
2541 href="../vhosts/name-based.html">name-based virtual hosts</a>.</p>
2544 <VirtualHost *><br />
2545 ServerName server.domain.com<br />
2546 ServerAlias server server2.domain.com server2<br />
2548 </VirtualHost>
2551 <seealso><a href="../vhosts/">Apache Virtual Host documentation</a></seealso>
2552 </directivesynopsis>
2555 <name>ServerName</name>
2556 <description>Hostname and port that the server uses to identify
2557 itself</description>
2558 <syntax>ServerName [<var>scheme</var>://]<var>fully-qualified-domain-name</var>[:<var>port</var>]</syntax>
2559 <contextlist><context>server config</context><context>virtual host</context>
2561 <compatibility>In version 2.0, this
2562 directive supersedes the functionality of the <directive>Port</directive>
2563 directive from version 1.3.</compatibility>
2566 <p>The <directive>ServerName</directive> directive sets the
2567 request scheme, hostname and
2568 port that the server uses to identify itself. This is used when
2569 creating redirection URLs. For example, if the name of the
2570 machine hosting the web server is <code>simple.example.com</code>,
2571 but the machine also has the DNS alias <code>www.example.com</code>
2572 and you wish the web server to be so identified, the following
2573 directive should be used:</p>
2576 ServerName www.example.com:80
2579 <p>If no <directive>ServerName</directive> is specified, then the
2580 server attempts to deduce the hostname by performing a reverse
2581 lookup on the IP address. If no port is specified in the
2582 <directive>ServerName</directive>, then the server will use the
2583 port from the incoming request. For optimal reliability and
2584 predictability, you should specify an explicit hostname and port
2585 using the <directive>ServerName</directive> directive.</p>
2587 <p>If you are using <a
2588 href="../vhosts/name-based.html">name-based virtual hosts</a>,
2589 the <directive>ServerName</directive> inside a
2590 <directive type="section" module="core">VirtualHost</directive>
2591 section specifies what hostname must appear in the request's
2592 <code>Host:</code> header to match this virtual host.</p>
2595 <p>Sometimes, the server runs behind a device that processes SSL,
2596 such as a reverse proxy, load balancer or SSL offload
2597 appliance. When this is the case, specify the
2598 <code>https://</code> scheme and the port number to which the
2599 clients connect in the <directive>ServerName</directive> directive
2600 to make sure that the server generates the correct
2601 self-referential URLs.
2604 <p>See the description of the
2605 <directive module="core">UseCanonicalName</directive> and
2606 <directive module="core">UseCanonicalPhysicalPort</directive>directives for
2607 settings which determine whether self-referential URLs (e.g., by the
2608 <module>mod_dir</module> module) will refer to the
2609 specified port, or to the port number given in the client's request.
2614 <seealso><a href="../dns-caveats.html">Issues Regarding DNS and
2615 Apache</a></seealso>
2616 <seealso><a href="../vhosts/">Apache virtual host
2617 documentation</a></seealso>
2618 <seealso><directive module="core">UseCanonicalName</directive></seealso>
2619 <seealso><directive module="core">UseCanonicalPhysicalPort</directive></seealso>
2620 <seealso><directive module="core">NameVirtualHost</directive></seealso>
2621 <seealso><directive module="core">ServerAlias</directive></seealso>
2622 </directivesynopsis>
2625 <name>ServerPath</name>
2626 <description>Legacy URL pathname for a name-based virtual host that
2627 is accessed by an incompatible browser</description>
2628 <syntax>ServerPath <var>URL-path</var></syntax>
2629 <contextlist><context>virtual host</context></contextlist>
2632 <p>The <directive>ServerPath</directive> directive sets the legacy
2633 URL pathname for a host, for use with <a
2634 href="../vhosts/">name-based virtual hosts</a>.</p>
2636 <seealso><a href="../vhosts/">Apache Virtual Host documentation</a></seealso>
2637 </directivesynopsis>
2640 <name>ServerRoot</name>
2641 <description>Base directory for the server installation</description>
2642 <syntax>ServerRoot <var>directory-path</var></syntax>
2643 <default>ServerRoot /usr/local/apache</default>
2644 <contextlist><context>server config</context></contextlist>
2647 <p>The <directive>ServerRoot</directive> directive sets the
2648 directory in which the server lives. Typically it will contain the
2649 subdirectories <code>conf/</code> and <code>logs/</code>. Relative
2650 paths in other configuration directives (such as <directive
2651 module="core">Include</directive> or <directive
2652 module="mod_so">LoadModule</directive>, for example) are taken as
2653 relative to this directory.</p>
2655 <example><title>Example</title>
2656 ServerRoot /home/httpd
2660 <seealso><a href="../invoking.html">the <code>-d</code>
2661 option to <code>httpd</code></a></seealso>
2662 <seealso><a href="../misc/security_tips.html#serverroot">the
2663 security tips</a> for information on how to properly set
2664 permissions on the <directive>ServerRoot</directive></seealso>
2665 </directivesynopsis>
2668 <name>ServerSignature</name>
2669 <description>Configures the footer on server-generated documents</description>
2670 <syntax>ServerSignature On|Off|EMail</syntax>
2671 <default>ServerSignature Off</default>
2672 <contextlist><context>server config</context><context>virtual host</context>
2673 <context>directory</context><context>.htaccess</context>
2675 <override>All</override>
2678 <p>The <directive>ServerSignature</directive> directive allows the
2679 configuration of a trailing footer line under server-generated
2680 documents (error messages, <module>mod_proxy</module> ftp directory
2681 listings, <module>mod_info</module> output, ...). The reason why you
2682 would want to enable such a footer line is that in a chain of proxies,
2683 the user often has no possibility to tell which of the chained servers
2684 actually produced a returned error message.</p>
2686 <p>The <code>Off</code>
2687 setting, which is the default, suppresses the footer line (and is
2688 therefore compatible with the behavior of Apache-1.2 and
2689 below). The <code>On</code> setting simply adds a line with the
2690 server version number and <directive
2691 module="core">ServerName</directive> of the serving virtual host,
2692 and the <code>EMail</code> setting additionally creates a
2693 "mailto:" reference to the <directive
2694 module="core">ServerAdmin</directive> of the referenced
2697 <p>After version 2.0.44, the details of the server version number
2698 presented are controlled by the <directive
2699 module="core">ServerTokens</directive> directive.</p>
2701 <seealso><directive module="core">ServerTokens</directive></seealso>
2702 </directivesynopsis>
2705 <name>ServerTokens</name>
2706 <description>Configures the <code>Server</code> HTTP response
2707 header</description>
2708 <syntax>ServerTokens Major|Minor|Min[imal]|Prod[uctOnly]|OS|Full</syntax>
2709 <default>ServerTokens Full</default>
2710 <contextlist><context>server config</context></contextlist>
2713 <p>This directive controls whether <code>Server</code> response
2714 header field which is sent back to clients includes a
2715 description of the generic OS-type of the server as well as
2716 information about compiled-in modules.</p>
2719 <dt><code>ServerTokens Prod[uctOnly]</code></dt>
2721 <dd>Server sends (<em>e.g.</em>): <code>Server:
2724 <dt><code>ServerTokens Major</code></dt>
2726 <dd>Server sends (<em>e.g.</em>): <code>Server:
2727 Apache/2</code></dd>
2729 <dt><code>ServerTokens Minor</code></dt>
2731 <dd>Server sends (<em>e.g.</em>): <code>Server:
2732 Apache/2.0</code></dd>
2734 <dt><code>ServerTokens Min[imal]</code></dt>
2736 <dd>Server sends (<em>e.g.</em>): <code>Server:
2737 Apache/2.0.41</code></dd>
2739 <dt><code>ServerTokens OS</code></dt>
2741 <dd>Server sends (<em>e.g.</em>): <code>Server: Apache/2.0.41
2744 <dt><code>ServerTokens Full</code> (or not specified)</dt>
2746 <dd>Server sends (<em>e.g.</em>): <code>Server: Apache/2.0.41
2747 (Unix) PHP/4.2.2 MyMod/1.2</code></dd>
2750 <p>This setting applies to the entire server, and cannot be
2751 enabled or disabled on a virtualhost-by-virtualhost basis.</p>
2753 <p>After version 2.0.44, this directive also controls the
2754 information presented by the <directive
2755 module="core">ServerSignature</directive> directive.</p>
2757 <seealso><directive module="core">ServerSignature</directive></seealso>
2758 </directivesynopsis>
2761 <name>SetHandler</name>
2762 <description>Forces all matching files to be processed by a
2763 handler</description>
2764 <syntax>SetHandler <var>handler-name</var>|None</syntax>
2765 <contextlist><context>server config</context><context>virtual host</context>
2766 <context>directory</context><context>.htaccess</context>
2768 <override>FileInfo</override>
2769 <compatibility>Moved into the core in Apache 2.0</compatibility>
2772 <p>When placed into an <code>.htaccess</code> file or a
2773 <directive type="section" module="core">Directory</directive> or
2774 <directive type="section" module="core">Location</directive>
2775 section, this directive forces all matching files to be parsed
2776 through the <a href="../handler.html">handler</a> given by
2777 <var>handler-name</var>. For example, if you had a directory you
2778 wanted to be parsed entirely as imagemap rule files, regardless
2779 of extension, you might put the following into an
2780 <code>.htaccess</code> file in that directory:</p>
2783 SetHandler imap-file
2786 <p>Another example: if you wanted to have the server display a
2787 status report whenever a URL of
2788 <code>http://servername/status</code> was called, you might put
2789 the following into <code>httpd.conf</code>:</p>
2792 <Location /status><br />
2794 SetHandler server-status<br />
2799 <p>You can override an earlier defined <directive>SetHandler</directive>
2800 directive by using the value <code>None</code>.</p>
2801 <p><strong>Note:</strong> because SetHandler overrides default handlers,
2802 normal behaviour such as handling of URLs ending in a slash (/) as
2803 directories or index files is suppressed.</p>
2806 <seealso><directive module="mod_mime">AddHandler</directive></seealso>
2808 </directivesynopsis>
2811 <name>SetInputFilter</name>
2812 <description>Sets the filters that will process client requests and POST
2814 <syntax>SetInputFilter <var>filter</var>[;<var>filter</var>...]</syntax>
2815 <contextlist><context>server config</context><context>virtual host</context>
2816 <context>directory</context><context>.htaccess</context>
2818 <override>FileInfo</override>
2821 <p>The <directive>SetInputFilter</directive> directive sets the
2822 filter or filters which will process client requests and POST
2823 input when they are received by the server. This is in addition to
2824 any filters defined elsewhere, including the
2825 <directive module="mod_mime">AddInputFilter</directive>
2828 <p>If more than one filter is specified, they must be separated
2829 by semicolons in the order in which they should process the
2832 <seealso><a href="../filter.html">Filters</a> documentation</seealso>
2833 </directivesynopsis>
2836 <name>SetOutputFilter</name>
2837 <description>Sets the filters that will process responses from the
2838 server</description>
2839 <syntax>SetOutputFilter <var>filter</var>[;<var>filter</var>...]</syntax>
2840 <contextlist><context>server config</context><context>virtual host</context>
2841 <context>directory</context><context>.htaccess</context>
2843 <override>FileInfo</override>
2846 <p>The <directive>SetOutputFilter</directive> directive sets the filters
2847 which will process responses from the server before they are
2848 sent to the client. This is in addition to any filters defined
2849 elsewhere, including the
2850 <directive module="mod_mime">AddOutputFilter</directive>
2853 <p>For example, the following configuration will process all files
2854 in the <code>/www/data/</code> directory for server-side
2858 <Directory /www/data/><br />
2860 SetOutputFilter INCLUDES<br />
2865 <p>If more than one filter is specified, they must be separated
2866 by semicolons in the order in which they should process the
2869 <seealso><a href="../filter.html">Filters</a> documentation</seealso>
2870 </directivesynopsis>
2873 <name>TimeOut</name>
2874 <description>Amount of time the server will wait for
2875 certain events before failing a request</description>
2876 <syntax>TimeOut <var>seconds</var></syntax>
2877 <default>TimeOut 300</default>
2878 <contextlist><context>server config</context></contextlist>
2881 <p>The <directive>TimeOut</directive> directive currently defines
2882 the amount of time Apache will wait for three things:</p>
2885 <li>The total amount of time it takes to receive a GET
2888 <li>The amount of time between receipt of TCP packets on a
2889 POST or PUT request.</li>
2891 <li>The amount of time between ACKs on transmissions of TCP
2892 packets in responses.</li>
2895 <p>We plan on making these separately configurable at some point
2896 down the road. The timer used to default to 1200 before 1.2,
2897 but has been lowered to 300 which is still far more than
2898 necessary in most situations. It is not set any lower by
2899 default because there may still be odd places in the code where
2900 the timer is not reset when a packet is sent. </p>
2902 </directivesynopsis>
2905 <name>TraceEnable</name>
2906 <description>Determines the behaviour on <code>TRACE</code>
2907 requests</description>
2908 <syntax>TraceEnable <var>[on|off|extended]</var></syntax>
2909 <default>TraceEnable on</default>
2910 <contextlist><context>server config</context></contextlist>
2911 <compatibility>Available in Apache 1.3.34, 2.0.55 and later</compatibility>
2914 <p>This directive overrides the behavior of <code>TRACE</code> for both
2915 the core server and <module>mod_proxy</module>. The default
2916 <code>TraceEnable on</code> permits <code>TRACE</code> requests per
2917 RFC 2616, which disallows any request body to accompany the request.
2918 <code>TraceEnable off</code> causes the core server and
2919 <module>mod_proxy</module> to return a <code>405</code> (Method not
2920 allowed) error to the client.</p>
2922 <p>Finally, for testing and diagnostic purposes only, request
2923 bodies may be allowed using the non-compliant <code>TraceEnable
2924 extended</code> directive. The core (as an origin server) will
2925 restrict the request body to 64k (plus 8k for chunk headers if
2926 <code>Transfer-Encoding: chunked</code> is used). The core will
2927 reflect the full headers and all chunk headers with the response
2928 body. As a proxy server, the request body is not restricted to 64k.</p>
2930 </directivesynopsis>
2933 <name>UseCanonicalName</name>
2934 <description>Configures how the server determines its own name and
2936 <syntax>UseCanonicalName On|Off|DNS</syntax>
2937 <default>UseCanonicalName Off</default>
2938 <contextlist><context>server config</context><context>virtual host</context>
2939 <context>directory</context></contextlist>
2942 <p>In many situations Apache must construct a <em>self-referential</em>
2943 URL -- that is, a URL that refers back to the same server. With
2944 <code>UseCanonicalName On</code> Apache will use the hostname and port
2945 specified in the <directive module="core">ServerName</directive>
2946 directive to construct the canonical name for the server. This name
2947 is used in all self-referential URLs, and for the values of
2948 <code>SERVER_NAME</code> and <code>SERVER_PORT</code> in CGIs.</p>
2950 <p>With <code>UseCanonicalName Off</code> Apache will form
2951 self-referential URLs using the hostname and port supplied by
2952 the client if any are supplied (otherwise it will use the
2953 canonical name, as defined above). These values are the same
2954 that are used to implement <a
2955 href="../vhosts/name-based.html">name based virtual hosts</a>,
2956 and are available with the same clients. The CGI variables
2957 <code>SERVER_NAME</code> and <code>SERVER_PORT</code> will be
2958 constructed from the client supplied values as well.</p>
2960 <p>An example where this may be useful is on an intranet server
2961 where you have users connecting to the machine using short
2962 names such as <code>www</code>. You'll notice that if the users
2963 type a shortname, and a URL which is a directory, such as
2964 <code>http://www/splat</code>, <em>without the trailing
2965 slash</em> then Apache will redirect them to
2966 <code>http://www.domain.com/splat/</code>. If you have
2967 authentication enabled, this will cause the user to have to
2968 authenticate twice (once for <code>www</code> and once again
2969 for <code>www.domain.com</code> -- see <a
2970 href="http://httpd.apache.org/docs/misc/FAQ.html#prompted-twice">the
2971 FAQ on this subject for more information</a>). But if
2972 <directive>UseCanonicalName</directive> is set <code>Off</code>, then
2973 Apache will redirect to <code>http://www/splat/</code>.</p>
2975 <p>There is a third option, <code>UseCanonicalName DNS</code>,
2976 which is intended for use with mass IP-based virtual hosting to
2977 support ancient clients that do not provide a
2978 <code>Host:</code> header. With this option Apache does a
2979 reverse DNS lookup on the server IP address that the client
2980 connected to in order to work out self-referential URLs.</p>
2982 <note type="warning"><title>Warning</title>
2983 <p>If CGIs make assumptions about the values of <code>SERVER_NAME</code>
2984 they may be broken by this option. The client is essentially free
2985 to give whatever value they want as a hostname. But if the CGI is
2986 only using <code>SERVER_NAME</code> to construct self-referential URLs
2987 then it should be just fine.</p>
2990 <seealso><directive module="core">UseCanonicalPhysicalPort</directive></seealso>
2991 <seealso><directive module="core">ServerName</directive></seealso>
2992 <seealso><directive module="mpm_common">Listen</directive></seealso>
2993 </directivesynopsis>
2996 <name>UseCanonicalPhysicalPort</name>
2997 <description>Configures how the server determines its own name and
2999 <syntax>UseCanonicalPhysicalPort On|Off</syntax>
3000 <default>UseCanonicalPhysicalPort Off</default>
3001 <contextlist><context>server config</context><context>virtual host</context>
3002 <context>directory</context></contextlist>
3005 <p>In many situations Apache must construct a <em>self-referential</em>
3006 URL -- that is, a URL that refers back to the same server. With
3007 <code>UseCanonicalPhysicalPort On</code> Apache will, when
3008 constructing the canonical port for the server to honor
3009 the <directive module="core">UseCanonicalName</directive> directive,
3010 provide the actual physical port number being used by this request
3011 as a potential port. With <code>UseCanonicalPhysicalPort Off</code>
3012 Apache will not ever use the actual physical port number, instead
3013 relying on all configured information to construct a valid port number.</p>
3015 <note><title>Note</title>
3016 <p>The ordering of when the physical port is used is as follows:<br /><br />
3017 <code>UseCanonicalName On</code></p>
3019 <li>Port provided in <code>Servername</code></li>
3020 <li>Physical port</li>
3021 <li>Default port</li>
3023 <code>UseCanonicalName Off | DNS</code>
3025 <li>Parsed port from <code>Host:</code> header</li>
3026 <li>Physical port</li>
3027 <li>Port provided in <code>Servername</code></li>
3028 <li>Default port</li>
3031 <p>With <code>UseCanonicalPhysicalPort Off</code>, the
3032 physical ports are removed from the ordering.</p>
3036 <seealso><directive module="core">UseCanonicalName</directive></seealso>
3037 <seealso><directive module="core">ServerName</directive></seealso>
3038 <seealso><directive module="mpm_common">Listen</directive></seealso>
3039 </directivesynopsis>
3041 <directivesynopsis type="section">
3042 <name>VirtualHost</name>
3043 <description>Contains directives that apply only to a specific
3044 hostname or IP address</description>
3045 <syntax><VirtualHost
3046 <var>addr</var>[:<var>port</var>] [<var>addr</var>[:<var>port</var>]]
3047 ...> ... </VirtualHost></syntax>
3048 <contextlist><context>server config</context></contextlist>
3051 <p><directive type="section">VirtualHost</directive> and
3052 <code></VirtualHost></code> are used to enclose a group of
3053 directives that will apply only to a particular virtual host. Any
3054 directive that is allowed in a virtual host context may be
3055 used. When the server receives a request for a document on a
3056 particular virtual host, it uses the configuration directives
3057 enclosed in the <directive type="section">VirtualHost</directive>
3058 section. <var>Addr</var> can be:</p>
3061 <li>The IP address of the virtual host;</li>
3063 <li>A fully qualified domain name for the IP address of the
3066 <li>The character <code>*</code>, which is used only in combination with
3067 <code>NameVirtualHost *</code> to match all IP addresses; or</li>
3069 <li>The string <code>_default_</code>, which is used only
3070 with IP virtual hosting to catch unmatched IP addresses.</li>
3073 <example><title>Example</title>
3074 <VirtualHost 10.1.2.3><br />
3076 ServerAdmin webmaster@host.foo.com<br />
3077 DocumentRoot /www/docs/host.foo.com<br />
3078 ServerName host.foo.com<br />
3079 ErrorLog logs/host.foo.com-error_log<br />
3080 TransferLog logs/host.foo.com-access_log<br />
3082 </VirtualHost>
3086 <p>IPv6 addresses must be specified in square brackets because
3087 the optional port number could not be determined otherwise. An
3088 IPv6 example is shown below:</p>
3091 <VirtualHost [2001:db8::a00:20ff:fea7:ccea]><br />
3093 ServerAdmin webmaster@host.example.com<br />
3094 DocumentRoot /www/docs/host.example.com<br />
3095 ServerName host.example.com<br />
3096 ErrorLog logs/host.example.com-error_log<br />
3097 TransferLog logs/host.example.com-access_log<br />
3099 </VirtualHost>
3102 <p>Each Virtual Host must correspond to a different IP address,
3103 different port number or a different host name for the server,
3104 in the former case the server machine must be configured to
3105 accept IP packets for multiple addresses. (If the machine does
3106 not have multiple network interfaces, then this can be
3107 accomplished with the <code>ifconfig alias</code> command -- if
3108 your OS supports it).</p>
3110 <note><title>Note</title>
3111 <p>The use of <directive type="section">VirtualHost</directive> does
3112 <strong>not</strong> affect what addresses Apache listens on. You
3113 may need to ensure that Apache is listening on the correct addresses
3114 using <directive module="mpm_common">Listen</directive>.</p>
3117 <p>When using IP-based virtual hosting, the special name
3118 <code>_default_</code> can be specified in
3119 which case this virtual host will match any IP address that is
3120 not explicitly listed in another virtual host. In the absence
3121 of any <code>_default_</code> virtual host the "main" server config,
3122 consisting of all those definitions outside any VirtualHost
3123 section, is used when no IP-match occurs. (But note that any IP
3124 address that matches a <directive
3125 module="core">NameVirtualHost</directive> directive will use neither
3126 the "main" server config nor the <code>_default_</code> virtual host.
3127 See the <a href="../vhosts/name-based.html">name-based virtual hosting</a>
3128 documentation for further details.)</p>
3130 <p>You can specify a <code>:port</code> to change the port that is
3131 matched. If unspecified then it defaults to the same port as the
3132 most recent <directive module="mpm_common">Listen</directive>
3133 statement of the main server. You may also specify <code>:*</code>
3134 to match all ports on that address. (This is recommended when used
3135 with <code>_default_</code>.)</p>
3137 <note type="warning"><title>Security</title>
3138 <p>See the <a href="../misc/security_tips.html">security tips</a>
3139 document for details on why your security could be compromised if the
3140 directory where log files are stored is writable by anyone other
3141 than the user that starts the server.</p>
3144 <seealso><a href="../vhosts/">Apache Virtual Host documentation</a></seealso>
3145 <seealso><a href="../dns-caveats.html">Issues Regarding DNS and
3146 Apache</a></seealso>
3147 <seealso><a href="../bind.html">Setting
3148 which addresses and ports Apache uses</a></seealso>
3149 <seealso><a href="../sections.html">How <Directory>, <Location>
3150 and <Files> sections work</a> for an explanation of how these
3151 different sections are combined when a request is received</seealso>
3152 </directivesynopsis>